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Oxidation and Cross-Linking in the Curing of Air-Drying Artists’ Oil Paints

  • Silvia Pizzimenti
    Silvia Pizzimenti
    Department of Chemistry and Industrial Chemistry, University of Pisa, Via Giuseppe Moruzzi 13, I-56124 Pisa, Italy
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    Orcidhttp://orcid.org/0000-0002-6230-5681
  • , 
  • Luca Bernazzani
    Luca Bernazzani
    Department of Chemistry and Industrial Chemistry, University of Pisa, Via Giuseppe Moruzzi 13, I-56124 Pisa, Italy
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  • , 
  • Maria Rosaria Tinè
    Maria Rosaria Tinè
    Department of Chemistry and Industrial Chemistry, University of Pisa, Via Giuseppe Moruzzi 13, I-56124 Pisa, Italy
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  • , 
  • Valérie Treil
    Valérie Treil
    Département de Chimie, Ecole normale supérieure de Lyon, 15 parvis René Descartes, Lyon 69342, France
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  • , 
  • Celia Duce*
    Celia Duce
    Department of Chemistry and Industrial Chemistry, University of Pisa, Via Giuseppe Moruzzi 13, I-56124 Pisa, Italy
    *Email: [email protected]
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    Orcidhttp://orcid.org/0000-0001-9354-7993
  • , and 
  • Ilaria Bonaduce*
    Ilaria Bonaduce
    Department of Chemistry and Industrial Chemistry, University of Pisa, Via Giuseppe Moruzzi 13, I-56124 Pisa, Italy
    *Email: [email protected]
    More by Ilaria Bonaduce
    Orcidhttp://orcid.org/0000-0003-0346-8373
Cite this: ACS Appl. Polym. Mater. 2021, 3, 4, 1912–1922
Publication Date (Web):March 16, 2021
https://doi.org/10.1021/acsapm.0c01441

Copyright © 2021 The Authors. Published by American Chemical Society. This publication is licensed under

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Abstract

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In this study, the chemistry of air-drying artist’s oil paint curing and aging up to 24 months was studied. The objective is to improve our molecular understating of the processes that lead to the conversion of the fluid binder into a dry film and how this evolves with time, which is at the base of a better comprehension of degradation phenomena of oil paintings and relevant to the artists’ paint manufacturing industry. To this aim, a methodological approach based on thermogravimetric (TG) analysis, differential scanning calorimetry (DSC), gas chromatography–mass spectrometry (GC–MS), and analytical pyrolysis coupled with gas chromatography and mass spectrometry (Py–GC–MS) was implemented. Model paintings based on linseed oil and safflower oil (a drying and a semidrying oil, respectively) mixed with two historically relevant pigments—lead white (a through drier) and synthetic ultramarine blue (a pigment often encountered in degraded painting layers)—were investigated. The oil curing under accelerated conditions (80 °C under air flow) was followed by isothermal TG analysis. The oxygen uptake profiles were fit by a semiempiric equation that allowed to study the kinetics of the oil oxidation and estimate oxidative degradation. The DSC signal due to hydroperoxide decomposition and radical recombination was used to monitor the radical activity over time and to evaluate the stability of peroxides formed in the paint layers. GC–MS was performed at 7 and 24 months of natural aging to investigate the noncovalently cross-linked fractions and Py–GC–MS to characterize the whole organic fraction of the model paintings, including the cross-linked network. We show that the oil–pigment combination may have a strong influence on the relative degree of oxidation of the films formed with respect to its degree of cross-linking, which may be correlated with the literature on the stability of painting layers. Undocumented pathways of oxidation are also highlighted.

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1. Introduction

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Paint consists of finely divided pigment particles—the discontinuous phase—dispersed in an organic fluid binder—the continuous phase. When a drying oil, which is a plant oil made of triglycerides of polyunsaturated fatty acids, is used as the binder, the paint is an oil paint. (1) Despite the introduction of synthetic paints, oil paints are still vastly used by artists due to their working properties and to the optical quality of the paint films they produce. (2) Plant oils are also employed to produce high-solid and water-borne (WB) formulations used in protective and decorative coatings. (1,3−5)
Oil binders cure by the action of oxygen, and films are formed through chemical reactions that solidify and harden the oil. The curing of an oil paint is an autoxidative process (6,7) involving the formation of peroxide species, which evolve the following two main competitive phenomena—cross-linking and oxidation. (1,8−11) Cross-linking is fundamental for obtaining a durable film that keeps the pigment particles together and adherent to the support.
Much research has investigated lipid oxidation (8,9) in the context of food, (6,7,12−16) lipid biochemistry, (17,18) and air-drying paints intended for industrial applications and the do-it-yourself market. (1,19−21) The complexity of reactions taking place over time in air-drying artistic oil paint layers is still the focus of research, especially in relation to degradation phenomena in paintings. (8,10,22−30)
Although pigments undergo chemical modifications that have an impact visually on the painting, the weakest link in the paint durability is the film former: (1) chemical changes in the continuous phase are reflected in changes in the mechanical properties of the paint layer, thus affecting its stability, and its response to the external environment and conservation interventions.
In heritage science, it is well known that the degradation of the organic film in an oil paint is strongly dependent on both internal and external factors such as the oil type, (11,31−33) the pigment(s), (10,28−30,32−37) additive(s), (1,21,28) artistic practices, (11,23,29,30) environmental conditions, (26,29,30,38) and conservation practices. (39,40) The chemical nature of the changes occurring in the film former as a consequence of degradation is, in most cases, not fully understood at the molecular level. It was recently hypothesized that some degradation phenomena taking place in oil paintings—especially those produced with modern manufactured artists’ oil paints (2)—are related to the chemical nature of the oil cross-linked network and, in particular, to a low degree of polymerization and a high degree of oxidation. (10,23,25,31,41)
Unfortunately, the molecular characterization of the polymeric network formed in a paint film is still a big challenge from an analytical point of view. (10) However, a useful approach to improve our understanding of the chemical structure of an oil polymeric film is to characterize the process leading to its formation: the curing.
In this work, the chemistry of oil curing and aging up to 24 months was studied in model paintings. Linseed and safflower oils were selected as drying and semidrying oils, respectively. Of the drying oils, linseed oil is one of the most commonly used oils in artistic paints. (42) Safflower oil is a semidrying oil due to its relatively lower content of unsaturations. (27) In modern times, it has been introduced into manufactured oil paints, (2) synthetic air-drying binders (e.g., alkyd resins), and solvent-borne and WB formulations. (1) In fact, due to the low linolenic acid content, it tends to yellow less than oils with a similar iodine value. (27)
As a paint system involves the presence of a pigment together with the film former, we started our study by selecting two historically and artistically relevant pigments with different effects on the oil curing: lead white (LW) and synthetic ultramarine blue (UB). LW has been historically the most important of all white pigments (43) and the most common is a synthetic pigment (44)—2PbCO3·Pb(OH)2. (43) Lead, in lead-based pigments, reacts with acidic moieties in oil paints to form RCOO–Pb–OOCR bonds, which are believed to make the paint more durable by increasing the cross-linking density. (37,45) Lead ions act as through driers, (21) which are able to efficiently catalyze the paint curing and accelerate oxygen uptake and autoxidation. (21,28,46) Synthetic UB is a sulfur-containing sodium aluminum silicate. Its general formula is (NaCa)8[Al6Si6O24](SO4,S,Cl)2, (43) and the deep blue color of the pigment is due to the sulfur-containing radical anions inside the aluminosilicate framework. (47) When synthetic ultramarine is mixed with a drying oil, the oil film dries slowly. (42) Paint layers with synthetic UB may present a degradation issue, the “ultramarine sickness”, which results in a gray appearance and a loss of detail in the artwork. (48)
Via a free radical process, synthetic UB photocatalyzes the degradation of the oil binder when UV radiation is present, (36) and both natural and synthetic UB can act as aluminosilicate catalysts. (49) UB also catalyzes the photodegradation of polyethylene when added as a pigment. (50,51) Burnstock et al. reported that ultramarine paint layers in modern oil paintings often present an important conservation issue: the paint is disrupted when saliva and water are used in the cleaning practice. (35) This phenomenon, called water sensitivity, has been hypothesized to be related in some cases to the lack of a well cross-linked oil network. (10,32)
In this study, a multianalytical methodological approach was implemented to systematically characterize the conversion of the liquid oil paint into a dry film by monitoring the formation of radical species, the reactions taking place with oxygen, and the consequent formation of new molecules.
Our approach is based on isothermal thermogravimetric (TG) analysis to study the kinetics of the oil oxidation and estimate the oxidative degradation, differential scanning calorimetry (DSC) to monitor the presence of hydroperoxides and active radicals over time and to evaluate the stability of peroxides formed in the paint layers, gas chromatography–mass spectrometry (GC–MS) to investigate the noncovalently cross-linked fractions, and analytical pyrolysis coupled with gas chromatography and mass spectrometry (Py–GC–MS) to characterize the whole organic fraction of the model paintings, including the cross-linked network. The model paintings were analyzed periodically over the course of 2 years with a variable frequency depending on the technique and the stage of curing of the paints.
The final aim is to improve our understanding of the curing of artistic air-drying oil paints, the phenomena that occur in a paint film over time and to correlate them to the characteristics and stability of the paint film.

2. Experimental Section

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2.1. Reagents

Methanol and water were purchased from Sigma-Aldrich (purity 99%). Lauric acid, suberic acid, myristic acid, azelaic acid, sebacic acid, palmitic acid, oleic acid, stearic acid, and tridecanoic acid were purchased from Sigma-Aldrich (purity 99%). Hexadecane acid isooctane, acetone, diethyl ether, and n-hexane were purchased from Sigma-Aldrich (high-performance liquid chromatography grade). N,O-Bis(-trimethylsilyl)-trifluoroacetamide with 1% trimethylchlorosilane (purity 98.5%) and 1,1,1,3,3,3-hexamethyldisilazane (HMDS) (purity 99.9 %) were purchased from Sigma-Aldrich.

2.2. Samples

Linseed oil and safflower oil were purchased from Maimeri (Milano, Italy). Synthetic UB and LW were purchased from Ferrario (Bologna, Italy) and Kremer (Germany), respectively. The systems analyzed in the present study were model oil paints and paintings created in the laboratory. Oil paints were prepared by mixing weighted amounts of drying oil and powdered pigment to obtain a workable impasto. Each oil paint was then used to prepare model oil paintings, casting the oil paints onto glass slides. The oil paintings were thus left to dry and cure under indoor laboratory conditions. Table 1 reports the detailed description of the oil paints.
Table 1. Description of Oil Paints
oil paintspigment(%)oil(%)
LWLOLW66linseed oil34
UBLOUB61linseed oil39
LWSOLW77safflower oil23
UBSOUB49safflower oil51

2.3. Drying Time

Paint drying, and in particular set-to-touch, dry-to-touch, and dry-hard-time, were measured according to ASTM D1640: standard test methods for drying, curing, or film formation of organic coatings at room temperature. The paints were cast on a glass slides to produce a homogeneous 0.45 mm wet film.

2.4. Thermogravimetric Analysis

A TA-Instruments thermobalance, model Q5000IR, was used for TG investigations and determination of the oxygen uptake under a constant air flow (25 mL/min) at 80 °C for 3000 min (2 days). The sample masses ranged between 6 and 9 mg. Temperature calibration was based on the Curie point of paramagnetic metals. A multipoint calibration with 5 Ci points from reference materials (Alumel, Ni, Ni 83% Co 17 %, Ni 63% Co 37%, and Ni 37% Co 63%) was performed. The oxygen uptake curves of the oil paints were normalized to the oil content. The fitting of the oxygen uptake curves was performed with the software OriginPro8.

2.5. Differential Scanning Calorimetry

DSC analyses were performed with a differential scanning calorimeter, Mettler Toledo DSC8222e, under constant nitrogen flow (80 mL/min) in the 30–300 °C temperature range, with a 10 °C/min heating rate. Samples (4–6 mg) were scratched from the cast of oil paint and placed in aluminum pans. DSC curves of the oil paint models were normalized to the oil content. Temperature and heat flow were calibrated using indium. The baseline was calibrated using two empty aluminum pans.

2.6. Gas Chromatography–Mass Spectrometry

For the GC–MS calibration, standard solutions of lauric acid (4.88 ppm), myristic acid (4.83 ppm), palmitic acid (4.95 ppm), oleic acid (4.78 ppm), stearic acid (4.97 ppm), azelaic acid (4.82 ppm), suberic acid (4.93 ppm), and sebacic acid (4.88 ppm) were prepared in acetone. Tridecanoic acid and hexadecane were used as internal standards for derivatization and injection. The samples’ weight ranged between 0.3 and 0.6 mg, and they were subject to alkaline hydrolysis, followed by acidification, extraction with an organic solvent, silylation, and GC–MS analysis. Details are reported elsewhere. (52) A gas chromatograph 6890 N GC system (Agilent Technologies, Palo Alto, CA, USA) coupled with a 5975 Mass Selective Detector (Agilent Technologies, Palo Alto, CA, USA) single quadrupole mass spectrometer was used. For the gas chromatographic separation, an HP-5ms fused silica capillary column (5%-diphenyl/95%-dimethyl polysiloxane, 30 m, 0.25 mm i.d., 0.25 mm film thickness (J&W Scientific, Agilent Technologies, Palo Alto, CA) with a deactivated silica precolumn (2 m, 0.32 mm i.d., (J&WScientific Agilent Technologies, Palo Alto, CA) was used. The PTV injector was used in split-less mode at 280 °C. The carrier gas was used in the constant flow mode (He, purity 99.995%) at 1.0 mL/min. The chromatographic oven was programmed as follows: initial temperature 80 °C, isothermal for 2 min; 10 °C/min up to 280 °C, and isothermal for 30 min. The MS transfer line temperature was 280 °C, the MS ion source temperature was 230 °C, and the MS quadrupole temperature was 150 °C. The mass spectrometer operated in electron impact (EI) positive mode (70 eV) with a scan range m/z 50–700. MS spectra were recorded both in TIC (total ion current) and single ion monitoring mode. Experiments were performed in triplicate.

2.7. Analytical Pyrolysis Coupled with Gas Chromatography and Mass Spectrometry

The instrumentation consisted of a microfurnace multishot pyrolyzer EGA/Py-3030D (Frontier Lab) coupled to a gas chromatograph 6890 (Agilent Technologies, Palo Alto, CA, USA) and to an Agilent 5973 Mass Selective Detector operating in EI mode at 70 eV. The split/split-less injector was used in split mode at 280 °C, with a split ratio 30:1. The chromatographic conditions were as follows: 50 °C isothermal for 2 min, 10 °C/min up to 280 °C and isothermal for 2 min, and 15 °C/min up to 300 °C and isothermal for 30 min. The carrier gas (He, purity 99.9995%) was used in the constant flow mode at 1.0 mL/min. The temperatures of the MS transfer line, MS ion source, and MS quadrupole were 280, 230, and 150 °C, respectively. The mass spectrometer was operated in EI positive mode (70 eV) with a scan range m/z 50–600. MS spectra were recorded in TIC mode. A total of 300 μg of the sample was placed in a pyrolysis cup and admixed to 5 μL HMDS used as a silylating agent for the in-situ derivatization of pyrolysis products. Analyses were performed in triplicate.

3. Results

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3.1. Drying Time

The drying time of the model paintings were measured according to the ASTM D1640 method. Set-to-touch, dry-to-touch, and dry-hard-time data are reported in Table 2.
Table 2. Set-to-Touch-Time (TSTT), Dry-to-Touch-Time (TDTT), and Dry-Hard Time (TDH) in Hours of Model Paintings
model oil paintTSTT (h)TDTT (h)TDH (h)
LWLO6390134
UBLO213242284
LWSO112157207
UBSO234261305
As expected, for both oil binders, LW-based paint layers dry faster than those based on UB. Also, for both pigments, safflower oil-based paint layers dry slower than those based on linseed oil.

3.2. Thermogravimetric Analysis

The oil curing under accelerated conditions was followed by TG analysis. Fresh oils and paints were cured at 80 °C for 3000 min in a thermobalance under airflow, and the oxygen uptake curve was registered (Figures 1, S1, and S2 in the Supporting Information). The temperature was chosen to ensure reasonable analysis time, as done in other works. (8,53−55) Although artistic paint layers do not normally cure at 80 °C, the method is a valid tool to compare in a highly reproducible way the oxidative behavior of the different oil paints. Curves up to 500 min are shown in Figure 1.

Figure 1

Figure 1. Oxygen uptake curves vs time of model oil paints. Curves are recorded under air flow at a constant temperature of 80 °C, and data are normalized for the oil content. (A) LO (solid gray line), LWLO (dashed and dotted light-blue line) and UBLO (dashed blue line); (B) SO (solid black line), LWSO (dashed and dotted red line), and UBSO (dashed pink line).

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All the paints show a rapid oxygen uptake in the first 2 h, with a mass increase in the range 3–7% due to the initial addition of oxygen (Figures 1, S1, and S2 in the Supporting Information). (8,52,55) The mass increase is followed by a region where a mass loss is evident due to the decomposition of oxygenated compounds formed, with the evolution of relatively low-molecular weight molecules. (8,56) The curve shape is a balance between the two phenomena, and for this reason, its visual investigation does not allow a straightforward comparison between the different paints. To adress this, we propose here eq 1 as a qualitative and descriptive equation for the oxygen uptake profiles.
(1)
(A, B, q, λi, t0 fitting parameters). Although eq 1 is intended as a qualitative and descriptive equation, it should reflect the kinetics of the overall process and the parameters therein should be interpreted accordingly. The use of this equation implicitly assumes that each of the processes involved in the oxygen uptake profiles is a first-order (or pseudo-first-order) process. Under non-limiting oxygen conditions, as in our experiments, the oxygen consumption is defined as a pseudo-first-order reaction with respect to the substrate concentration. (57,58) The mass increase ascribed to the oxygen addition is hence described by a sigmoidal function 1/[1 + e–λ0(t–t0)], which also allows to account for an induction time (if present). The two other exponential processes (e–λ1t and e–λ2t) are relative to mass losses. The mass loss can be associated with the evolution of different molecules including aldehydes and ketones and is generally ascribed to the exponential decomposition of hydroperoxides. (59,60) A descriptive equation with only one exponential to describe the mass loss was also tried but did not prove satisfactory (Figure S1 in Supporting Information). The meaning of the parameters should be as follows:

  • A is the overall mass loss

  • B is the asymptote of mass % curve for t that tends to infinity

  • λ0 is the apparent time constant for the oxygen uptake process

  • λ1, λ2 are the apparent time constants for the two main mass loss phenomena

  • q, (1 – q) are the relative weights of the two relevant processes that are responsible for the mass loss

  • t0 is the abscissa of the inflexion point of the sigmoidal function related to the induction time of the oxygen uptake process

The fitting parameters obtained are reported in Table 3 and the fitted curves in Figure S2 in the Supporting Information.
Table 3. Values of Parameters and Their Standard Error in Brackets; Χ2 and R2 Coefficients Obtained by Fitting the Oxygen Uptake Profiles with eq 1 for LO, LWLO, UBLO, SO, LWSO, and UBSO
model paintsABCqλ0 × 10 (min–1)λ1 × 102 (min–1)λ2 × 104 (min–1)t0 (min)Χ2 × 103R2
LO10.81398.5769.250.5990.4500.3924.3640.30.340.99987
 (0.004)(0.003) (<0.001)(<0.001)(<0.001)(0.01)(<0.1)  
LWLO5.65997.8363.470.3991.1040.7804.715.80.600.99933
 (0.004)(0.002) (<0.001)(0.003)(0.002)(0.01)(<0.1)  
UBLO9.6298.0797.180.5710.3280.3675.1362.41.330.99938
 (0.01)(0.005) (0.001)(0.001)(0.001)(0.02)(0.1)  
SO12.6195.3317.320.7280.2990.6306.2026.41.490.99935
 (0.02)(0.002) (<0.001)(0.001)(0.001)(0.02)(0.1)  
LWSO15.3191.9747.280.5970.7981.5004.950.93.860.99888
 (0.03)(0.004) (<0.001)(0.005)(0.005)(0.01)(0.1)  
UBSO20.9094.05713.630.7760.1280.5946.0887.33.980.99881
 (0.20)(0.004) (0.001)(<0.001)(0.003)(0.02)(0.8)  

3.2.1. Mass Uptake

λ0 and t0 values show that LW catalyzes the mass uptake both in linseed oil—in agreement with previous observations (28,46)—and safflower oil, as the apparent time constants are both about one order of magnitude bigger than those of the corresponding oils alone, and t0 values are one order of magnitude smaller. As far as UB-based paints are concerned, the one with linseed oil presents a similar apparent time constant and the same order of magnitude but the bigger value of t0, with respect to the oil alone, indicating that UB causes a small acceleration of the oxygen uptake in linseed oil. UBSO paint is the one that presents the lowest apparent time constant (1 order of magnitude smaller than the oil alone) and the biggest t0, resulting in the paint with the slowest oxygen uptake.
The C parameter in Table 3, estimated as C = A·[q·e(−λ1tonset) + (1 – q)·e(−λ2tonset)], allows us to estimate the mass of oxygen taken by the paint with time, without taking into consideration further reactions. If we compare the oils alone, LO and SO show similar values, with LO being slightly bigger than SO, in agreement with the iodine numbers of these oils. (61) Things change significantly when pigments are added. LW halves the amount of oxygen that is added to linseed oil, while very similar values are obtained in the case of safflower oil. UB reduces, although of a lower extent than LW, the amount of oxygen added to linseed oil but doubles the amount of oxygen added when safflower oil is concerned. Oxygen adds to alkyl radicals formed upon hydrogen abstraction, with formation of peroxyl radicals. Oxygen is also added in other possible reactions, including internal rearrangement, addition to double bonds, and recombination of peroxyl radicals. (10) The fact that LW reduces the amount of oxygen taken by the oil can be interpreted as a consequence of the evolution of unsaturated fatty acids through other reaction pathways—cross-linking—and a low occurrence of the abovementioned reactions of peroxyl radicals. (10) UB on the other hand, adds always more oxygen than LW (double), and in the case of safflower oil, also more than the oil alone. We can interpret this as a result of low evolution of polyunsaturated fatty acids through cross-linking and a high degree of oxidation. (10)

3.2.2. Mass Loss

The scission of alkoxy radicals deriving from the peroxidation of unsaturated triglyceride fatty acids has been long discussed, and it leads mainly to the formation of hydrocarbons, furans, and oxo- and hydroxy-fatty acids with a shorter chain length. (6,14,62) Among these, several are volatile molecules, and many of them can also further react to produce other oxo- and hydroxy-fatty acids with a shorter chain length. (6,14,62)
The fitting clearly shows that there are two phenomena (1 and 2) which are responsible for a mass loss, and each phenomenon must be intended as a combination of reactions which lead, among other things, to the formation of low-molecular-weight molecules. The two mass loss phenomena—1 and 2—are, respectively, the fastest and the slowest one. In the case of LW with linseed oil, the first mass loss phenomenon has a smaller weight than the second one (q), meaning that the mass loss occurring because of the first phenomenon leads to a smaller mass loss than the one due to the slower phenomenon. The opposite is true for all other paints.
The A values represent the total mass loss, observed as a consequence of both 1 and 2 phenomena. As the mass loss is a consequence of oxidative degradation, (8) which competes with cross-linking, a higher mass loss can be used as an index of a higher extent of lipid oxidation, as opposed to the lipid cross-linking. LW with linseed oil is the paint with the lowest mass loss. UB causes a higher mass loss in all paints, and SO-based paints have always a higher mass loss than LO-based paints.

3.3. Differential Scanning Calorimetry

The curing of the oil paints was monitored by DSC with a dynamic method under a nitrogen flow. (8,63,64) DSC analyses were performed on samples collected from the model paintings, starting from the time zero (t0) and then on regular time intervals up to 24 months (see Figures 2, S3 and S4 in the Supporting Information). Table 4 shows the extrapolated onset temperature (Tonset) and the maximum temperature (Tpeak) of the DSC profiles acquired. An endothermic effect above 200 °C was observed in the LW paint layers, due to pigment decomposition, but was not recorded as it was not relevant to this study.

Figure 2

Figure 2. DSC curves—normalized to the oil content—of model oil paintings recorded up to 24 months of natural aging. (A) LWLO (light blue line); (B) UBLO (blue line); (C) LWSO (red line); (D) UBSO (pink line).

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Table 4. Onset Temperature Tonset (°C) and Maximum Temperature Tpeak (°C) Extrapolated from DSC Curves vs Curing Time of Model Oil Paintings
 LWLOUBLOLWSOUBSO
 Tonset (°C)Tpeak (°C)Tonset (°C)Tpeak (°C)Tonset (°C)Tpeak (°C)Tonset (°C)Tpeak (°C)
1 day95119  99129  
2 days90127  95127  
3 days9511610816297125115171
7 days91108921418710797138
9 days9111488140769885144
14 days9111197149699197144
1 month  100161  103154
2 months  110155  118146
3 months  125147  114136
4 months  122142  112142
5 months  120142  110132
6 months  117139  108129
7 months  102136  105125
24 months        
At the beginning, no signals were observed until the formation of peroxides and radical species occurred, at which point an (overall) exothermic heat effect appeared and changed with the sample age. The exothermic effect is due to different overlapping phenomena: the decomposition of peroxides and hydroperoxides, which is endothermic, and the recombination of radical species—those deriving from the peroxides and hydroperoxides decomposed, as well as other radicals species present in the paint film (such as R•, RO•, and ROO•)—which is exothermic. (55,63,64) The area of the peak recorded is thus proportional to the sum of the number of broken peroxide bonds and free radical species present in a sample at a given time. When the exothermic signal decreases to almost zero, we can assume that the concentration of the active species is very low. (63−65) This does not necessarily mean that the chemical drying is complete, as double bonds might still be present, and thus susceptible to further reactions. In the temperature range observed, the evaporation (endothermic effect) of small volatile oxygenated products of oxidation can also be observed at higher temperatures, if not superimposed to the main exothermic peak.
The DSC curves of LW containing paint layers show similar shapes, and an exothermic heat effect in the temperature range 90–130 °C for LWLO and 70–135 °C for LWSO is observed. The maximum intensity is reached after 2 days in LWLO and after 3 days in LWSO (Figure 2A,C and, Table 4). The DSC curves of UB containing paint layers show similar shapes and an exothermic broader heat effect in the temperature range 70–190 °C, starting after 3 days and reaching the maximum value after 7 days (Figure 2B,D and Table 4). The delay in the peak appearance in UB-based paints confirms the results on the catalytic effect of LW and the retardant effect of UB on peroxide radical formation observed in the oxygen uptake curves.
The Tonset of the peak, indicating the starting temperature of peroxide decomposition, follows the trend: Tonset (LWLO) < Tonset (LO) < Tonset (UBLO) and Tonset (LWSO) < Tonset (SO) < Tonset (UBSO) (Figures S3 and 2, Tables 4, S1 and S2 in the Supporting Information). The DSC nonisothermal measurement can assess the thermal stability of the peroxides resulting from autoxidation. (65) The trend of Tonset values indicates that LW leads to the formation of less stable peroxides, while UB to more stable ones (Table 4).
Under experimental conditions adopted, active species (peroxides and free radicals) could not be detected after almost 2 months in LW-based paint layers, while for UB ones, a calorimetric signal was still present after 7 months. This indicates a catalytic effect of LW and a retardant effect of UB also on the cross-linking. This retardant effect of UB can also be linked to the observed stabilization of the peroxides operated by the pigment. The decomposition of hydroperoxides is considered to be the key rate-limiting step based on the fact that it is the only propagation step involving any significant activation energy. (12) If a peroxide is stabilized by UB, the activation energy for its decomposition becomes higher, and other reaction pathways (10,13,14) might become predominant.

3.4. Gas Chromatography–Mass Spectrometry

GC–MS analyses were performed at 7 and 24 months of natural aging, after saponification, hydrolysis, and derivatization, to investigate the fractions of the oil phase noncovalently cross-linked (through C–C and C–O–C bonds). The TICs (total ion chromatograms) are reported in Figures S5, S6, S7, and S8 in the Supporting Information. The compounds identified are listed in Table S3. Quantitative analyses of mono- and dicarboxylic acids were performed, and data are reported in Table 5.
Table 5. Characteristic Parameters Relative to Samples from Model Oil Paintings Analyzed by GC–MS after 7 and 24 Months of Natural Aginga
 P/SA/PO/S∑Dic. %
 7 m24 m7 m24 m7 m24 m7 m24 m
LWLO1.1 ± 0.01.6 ± 0.22.0 ± 0.02.1 ± 1.00.0 ± 0.00.0 ± 0.053.0 ± 5.658.7 ± 11.7
UBLO1.3 ± 0.11.7 ± 0.23.0 ± 0.51.8 ± 0.80.0 ± 0.00.0 ± 0.063.7 ± 3.856.3 ± 9.6
LWSO2.2 ± 0.43.0 ± 1.26.1 ± 1.01.3 ± 0.10.1 ± 0.10.1 ± 0.081.1 ± 1.552.6 ± 2.8
UBSO2.0 ± 0.43.4 ± 1.13.1 ± 1.10.4 ± 0.10.1 ± 0.10.0 ± 0.067.4 ± 8.534.5 ± 9.4
a

Confidence intervals are reported, calculated at 95% confidence level. P/S: palmitic acid (hexadecanoic) to stearic acid (octadecanoic) ratio, A/P: azelaic acid (nonanedioic acid) to palmitic acid ratio, O/S: oleic acid ((9Z)-octadec-9-enoic acid) to stearic acid ratio, ∑Dic. %: sum (%) of the dicarboxylic acids – suberic acid (octanedioic acid), azelaic acid, and sebacic acid (decanedioic acid).

Most relevant, after 24 months of natural aging is the fact that in safflower-based paints, the relative content of azelaic acid is significantly decreased with respect to the values recorded after 7 months. To the best of our knowledge, this is the first time that such a decrease is observed. Azelaic and other dicarboxylic acids, formed by oxidation of (poly)unsaturated fatty acids, are considered final products of oxidation. (24) The data presented here clearly demonstrate that they are not, and there must be reaction pathways that lead to their decomposition into other reaction products. Such products were not identified in the chromatograms. A possible explanation is that these compounds, due to their low molecular weight, might have retention times lower than the solvent delay of the chromatographic run. Another possible explanation is that dicarboxylic acids might become covalently bound (through C–C and C–O–C bonds) to the cross-linked network. The fact that such decrease was not observed for linseed oil paints might mean that these reactions do not take place in linseed oil to a significant extent or that we have missed the point where the relative content of dicarboxylic acids reached a maximum and then decreased, which must have occurred before 7 months. Considering the faster kinetics of curing of linseed oil-based paints, this hypothesis is not to be excluded.
Hydroxyacids—intermediate products of oxidation (52)—were investigated and detected in all chromatograms and were identified by mass spectral interpretation and by comparison with the available literature. (66) α-Hydroxyacids and α-hydroxy di-acids ranging from 5 to 10 carbon atoms were detected both after 7 and 24 months in all samples (chromatographic profiles in Figures S5–S9, and Table S3, and mass spectra Figure S9–S18 in the Supporting Information). The formation of α-hydroxyacids and α-hydroxy di-acids ranging from 5 to 10 carbon atoms could be justified as the consequence of oxidation of double bonds followed by β-elimination, given the position of double bonds in oleic, linoleic, and linolenic acids. (7) α-Hydroxy hexadecanoic and α-hydroxyl octadecanoic acid (mass spectra in Figures S19 and S20 in the Supporting Information) were only detected at 24 months of natural aging. Their formation can only be ascribed to the oxidation of palmitic and stearic acid in position α and have never been reported, to the best of our knowledge, in the context of curing and autoxidation of glycerolipids.

3.5. Analytical Pyrolysis Coupled with Gas Chromatography and Mass Spectrometry

Py–GC–MS enabled the investigation of the whole organic fraction of the paints, including the cross-linked network. The extracted ion chromatograms of m/z 129 ascribable to silylated carboxylic acid moieties obtained at 7 and 24 months of natural aging are shown in Figures 3 and S21. The complete list of the identified compounds is reported in Table S3.

Figure 3

Figure 3. Extracted ion pyrograms of m/z 129 of model oil paintings after 7 (7 m) and 24 months (24 m) of natural aging. In the insets, the chromatographic profiles of unsaturated fatty acids are reported. m/z 339: octadecenoic acid (oleic acid), m/z: 337: octadecadienoic acid (linoleic acid). As reference, the extract ion of octadecanoic acid (stearic acid) is reported (m/z: 341). (A) LWLO; (B) UBLO; (C) LWSO; (D) UBSO.

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Pyrolytic profiles are strongly affected by the pigment nature. (25,67) It is thus in general not possible to compare pyrograms of samples containing different pigments, but the comparison between chromatographic profiles of samples collected from the same paint layers at different stages of aging is still possible. Short-chain linear carboxylic acids, saturated and ω-unsaturated, ranging from 6 to 12, and peaking at 8, are the products of pyrolysis of the cross-linked network. (55) LW-based paints at both 7 and 24 months of natural aging are quite similar, and only a slight increase in the relative intensity of the peaks ascribable to the pyrolysis of the cross-linked network is observable at longer curing times (Figure 3A,C). This suggests that the relative content of the cross-linked network is relatively increased with time, as expected of a curing oil paint film. The opposite, though, is observed in UB-based paints (Figure 3B,C), suggesting that the degradative oxidation of the cross-linked network is taking place.
In the pyrogram of UBLO, LWSO and UBSO unsaturated compounds were detected: high amounts of oleic acid)—which is significantly higher than in GC–MS chromatogram; trans-octadec-9-enoic acid; 8-hydroxydec-9-enoic acid; 8-hydroxyundec-10-enoic acid; and 9-hydroxyoctadec-12-enoic acid (the molecular structure was tentatively assigned based on the mass spectra reported in Figure S22 in the Supporting Information). Given their absence in the GC–MS chromatograms, these compounds must be ascribed to the pyrolysis of (unsaturated fatty) acids covalently bound (through C–C and C–O–C bonds) to the cross-linked network. UBLO and UBSO paints both present a thermal effect still after 24 months of curing, but LWSO did not present any thermal effect after 2 months (see DSC results and Figure 2). This confirms that although active radical species may be very low in abundance in paint layers, unsaturations may still be still present, available for further reactions.

4. Discussion

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A scheme to summarize the principal findings is reported in Figure 4.

Figure 4

Figure 4. Summary of the principal results obtained in the study.

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The thermal behavior of the paints and molecular profiles of the painting layers clearly confirm that the curing of oil paints is dependent on both the type of oil and the pigment.
Safflower oil, which is considered a semidrying oil, shows a very different behavior with respect to linseed oil. Oxidative degradative phenomena start earlier, and they are faster. Safflower oil is also more subject to reaction pathways lead by peroxyl radicals, which favor oxidation. (13,14) All these features can be correlated to the reactivity of bis-allylic positions and their lower content in linolenic acid—the main fatty acid in safflower oil, compared to linolenic acid—the main fatty acid of linseed oil. (10)
In a painting layer containing LW, after 7 months of natural curing, most active species are absent, or present at very low concentrations, especially in linseed oil-based paintings. It is well known that LW is a through drier, which catalyzes both the initiation and autoxidation in an oil paint. (28) TG and DSC data in the present study show that LW catalyzes the oxygen uptake to form peroxides—the initiation step of autoxidation reactions, in agreement with the observed behavior of other primary and through driers, (28,54) as well as the cross-linking and volatile formation and evolution. We showed for the first time that LW decreases the stability of the peroxides (DSC). This can be directly linked to the catalytic effect of LW both in the cross-linking reaction and volatile formation. All techniques used show that the effect of LW on the reactivity of polyunsaturated triglyceride fatty acids is oil-dependent, and double bond consumption is faster when a drying oil is used.
Synthetic UB was shown in this study to have a retardant effect on the oxygen uptake and radical peroxide formation respect with the oils alone and LW-based paints (TG and DSC). UB was proven to stabilize the peroxides formed upon oxygen uptake (DSC), affecting the curing kinetics and, possibly favoring alternative reaction pathways with respect to those typical of autoxidation reactions. (10,13,14) UB-based paint films are subject to a higher degree of oxidation than LW-based ones (GC–MS); the formation and evolution of volatile compounds are slower and continue for a longer time (TG, DSC), competing with the formation of a stable cross-linked network. This is also evident by analyzing the pyrolysis data, which show that the cross-linked network of UB model painting gets degraded with time, most likely to the advantage of oxidative degradation reactions. This observation is in agreement with the work of de la Rie et al., (36) which demonstrated the physical disruption of the oil binder UB-based paintings upon light aging. Moreover, it strongly supports the hypothesis that synthetic UB paint layers may commonly present water sensitivity, caused by a poorly established cross-linked network, and the presence of relatively high amounts of polar oxidized (relatively low molecular weight) species. (10,32)
Mass spectrometric data show that dicarboxylic acids formed upon curing (in safflower oil-based paints) reach a maximum and then decrease (GC–MS). Moreover, short α-hydroxy dicarboxylic acids (from 8 to 10 carbons) were detected both at 7 and 24 months of natural aging, and α-hydroxy hexadecanoic and octadecanoic acids were detected at 24 months of natural aging. This proves that oxidation in alpha to the carbonyl moiety can take place upon curing. These data are extremely interesting, as they confirm the hypothesis (10,13,14) that the reaction pathways involved in the curing of a drying oil are much more than those reported in the literature and include several possible paths for oxidative degradation, including the progressive oxidation of fatty acids in position α to the carbonyl moieties. This phenomenon has never been observed before, although recently, the hypothesis that the position α to the carbonyl moiety might be susceptible to oxidation in glycerolipids has been advanced, in relation to the formation, upon further oxidation, of oxalic acid. (10) Insoluble salts of oxalic acid are largely detected in aged oil paintings, (68,69) also in association with UB paints. (70) The presence in the painting films of α-hydroxyl hexadecanoic and octadecanoic acids, strongly supports this hypothesis, as further oxidation of the hydroxyl moiety would lead to oxoacetic acid, and, ultimately, to oxalic acid. Oxidation of carboxylic acids in alpha to carboxylic moieties upon curing contradicts two common assumptions normally made in the molecular analysis of artists’ oil painting layers. The first is that saturated fatty acids as palmitic and stearic acids are stable and are thus not subject to any reaction in the formation of a mature oil paint film (besides metal soap formation). The second is that the azelaic-to-palmitic acid ratio is as an index of the degree of oxidation of an oil paint.

5. Conclusions

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In this study, a multianalytical approach was implemented in order to investigate the curing and maturing of air-drying artistic oil paints during 24 months of natural aging. The final aim is to improve our understanding of the curing of artistic air-drying oil paints, the phenomena that may take place in a paint film with time, and try to correlate them to the paint film characteristics and stability. The study was carried out on model paints based on linseed oil (a drying oil) and safflower oil (a semidrying oil) with two different pigments: LW, a through drier, and UB, which has been often correlated with degradation phenomena of modern oil paintings.
When in a painting layer, an oil—both drying and semidrying oil, is mixed with LW, the oil mobile phase converts quickly in a well cross-linked network and presents a relatively low degree of oxidation. Painting layers containing synthetic UB show a very different behavior, especially when a semidrying oil is used. On the whole, it is clear that increased levels of oxidative degradation occur in synthetic UB paintings in comparison to LW ones and significantly the more so when UB is used in combination with safflower oil. As a result, we can expect that an UB painting layer is less cross-linked than a LW-based one when other factors (oil type, additives, age, conservation conditions, etc.) are the same.
This tendency of UB to favor oxidative degradation over cross-linking may be related to documented conservation issues of ultramarine paining layers, from the loss of cohesion to the establishment of water sensitivity.

Supporting Information

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The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsapm.0c01441.

  • Experimental and fitted oxygen uptake profiles of linseed oil obtained by the equation with only one exponential and by eq 1; experimental and fitted oxygen uptake profiles of oils and model oil paints by eq 1; DSC curves of oils and model oil paints; Tonset, Tpeak of the normalized DSC curves for oils and model oil paints; list of compounds identified as trimethylsilyl derivatives in the chromatograms obtained by GC–MS and Py–GC–MS of model oil paints; total ion chromatograms obtained by GC–MS analysis of model oil paints; mass spectra of α- and β-hydroxyacids obtained with GC–MS; extracted ion pyrograms of m/z 129 of model oil paints; and mass spectra attributed to 8-hydroxydec-9-enoic acid, 8-hydroxyundec-10-enoic acid and 9-hydroxyoctadec-12-enoic acid obtained with Py–GC–MS (PDF)

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Author Information

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  • Corresponding Authors
  • Authors
    • Silvia Pizzimenti - Department of Chemistry and Industrial Chemistry, University of Pisa, Via Giuseppe Moruzzi 13, I-56124 Pisa, Italy;  Orcidhttp://orcid.org/0000-0002-6230-5681
    • Luca Bernazzani - Department of Chemistry and Industrial Chemistry, University of Pisa, Via Giuseppe Moruzzi 13, I-56124 Pisa, Italy
    • Maria Rosaria Tinè - Department of Chemistry and Industrial Chemistry, University of Pisa, Via Giuseppe Moruzzi 13, I-56124 Pisa, Italy
    • Valérie Treil - Département de Chimie, Ecole normale supérieure de Lyon, 15 parvis René Descartes, Lyon 69342, France
  • Notes
    The authors declare no competing financial interest.

Acknowledgments

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This work was performed within the context of the JPI CMOP project: “Cleaning of Modern Oil Paints” (Heritage Plus Joint Call project 2015–2018).

References

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This article references 70 other publications.

  1. 1
    Honzíček, J. Curing of Air-Drying Paints: A Critical Review. Ind. Eng. Chem. Res. 2019, 58, 12485– 12505,  DOI: 10.1021/acs.iecr.9b02567
    Google Scholar
    1
    Curing of Air-Drying Paints: A Critical Review
    Honzicek, Jan
    Industrial & Engineering Chemistry Research (2019), 58 (28), 12485-12505CODEN: IECRED; ISSN:0888-5885. (American Chemical Society)
    A review. This review provides an overview of air-drying binders and chem. processes responsible for their solidification and hardening. It is focused not only on binders derived from plant oils but also on oriental lacquers and their synthetic congeners as their curing is also based on chem. reactions with air-oxygen. The main aim of this review is to bring a crit. view on the mechanism of the autoxidn. process relevant to paint technol. and highlight the previous misinterpretation, remaining open questions, and gaps in the current state of knowledge. Such an objective was achieved by utilization of the latest knowledge appearing in various areas of the chem. research, e.g., org. chem., biochem., phys. chem., computational chem., and inorg. chem. Considerable attention is also given to recent developments in the field of transition metal driers and additives including clarification the role of cobalt-based driers and an updated overview of cobalt replacement.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXht1aqsb3J&md5=3d574a68e8897a37756a5d9b16308be2
  2. 2
    Burnstock, A.; van den Berg, K. J. Twentieth century oil paint. The interface between science and conservation and the challenges for modern oil paint research. Issues in Contemporary Oil Paint; Springer, 2014; pp 1– 19.
    Google Scholar
    There is no corresponding record for this reference.
  3. 3
    Hofland, A. Alkyd resins: From down and out to alive and kicking. Prog. Org. Coat. 2012, 73, 274– 282,  DOI: 10.1016/j.porgcoat.2011.01.014
    Google Scholar
    3
    Alkyd resins: From down and out to alive and kicking
    Hofland, Ad
    Progress in Organic Coatings (2012), 73 (4), 274-282CODEN: POGCAT; ISSN:0300-9440. (Elsevier B.V.)
    A review. Alkyd resins have been introduced in the 1930s as binders for paints. They are suitable for the prodn. of a very broad range of coating materials. When properly formulated, alkyd emulsions can be considered as candidates to formulate paints with a zero VOC level. This paper summarizes the new developments in alkyd emulsions and high solid alkyd paints and compares these paint systems with paints based on acrylic dispersions as other environmentally friendly alternatives to conventional paints.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XjtVOrtrk%253D&md5=a1e308af020ad3eaecebd1d9f160ce92
  4. 4
    Lindeboom, J. Air-drying high solids alkyd pants for decorative coatings. Prog. Org. Coat. 1998, 34, 147– 151,  DOI: 10.1016/s0300-9440(98)00034-4
    Google Scholar
    4
    Air-drying high solids alkyd paints for decorative coatings
    Lindeboom, Jan
    Progress in Organic Coatings (1998), 34 (1-4), 147-151CODEN: POGCAT; ISSN:0300-9440. (Elsevier Science S.A.)
    A review with 3 refs.; the restrictions on the emission of solvents in paints makes the need for environmentally-friendly systems still more important. For industrial applications, powder coatings and water-borne systems are the most attractive alternatives and are already in use. For architectural purposes, there is a min. acceptance of water-borne systems (except wall paints). In this application, high solids are becoming more and more accepted as an alternative to traditional systems, not only because of their environmental effects but also for their tech. performance and economical benefits.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXkvFKjtrg%253D&md5=7be9c7c844f6fe71ca2d4e4186a30a96
  5. 5
    Athawale, V. D.; Nimbalkar, R. V. Waterborne coatings based on renewable oil resources: an overview. J. Am. Oil Chem. Soc. 2011, 88, 159– 185,  DOI: 10.1007/s11746-010-1668-9
    Google Scholar
    5
    Waterborne Coatings Based on Renewable Oil Resources: an Overview
    Athawale, Vilas D.; Nimbalkar, Ramakant V.
    Journal of the American Oil Chemists' Society (2011), 88 (2), 159-185CODEN: JAOCA7; ISSN:0003-021X. (Springer)
    A review. Polyurethane dispersions are gaining in importance due to their environmentally friendly coating system, versatile coating properties and ease of application. An enormous amt. of research is focused on waterborne coatings such as waterborne alkyds, water-reducible alkyds, alkyd-acrylic hybrids, oil modified polyurethane dispersions and their composite latexes. This review gives a comprehensive compilation of recent studies on the synthesis and applications of waterborne coatings. The article specifically covers all of the research work carried out in the field of waterborne alkyd-acrylics, polyurethane dispersions and their hybrid latexes systematically.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhvVajsbw%253D&md5=e2afb380e10a8b4fddcb202b08925aea
  6. 6
    Frankel, E. N. Lipid Oxidation; Woodhead Publishing Limited: Cambridge, 2012.
    Google Scholar
    There is no corresponding record for this reference.
  7. 7
    Shahidi, F. Bailey’s Industrial Oil and Fat Products, Edible Oil and Fat Products: Processing Technologies; John Wiley & Sons, 2005; Vol. 5.
    Google Scholar
    There is no corresponding record for this reference.
  8. 8
    Lazzari, M.; Chiantore, O. Drying and oxidative degradation of linseed oil. Polym. Degrad. Stab. 1999, 65, 303– 313,  DOI: 10.1016/s0141-3910(99)00020-8
    Google Scholar
    8
    Drying and oxidative degradation of linseed oil
    Lazzari, Massimo; Chiantore, Oscar
    Polymer Degradation and Stability (1999), 65 (2), 303-313CODEN: PDSTDW; ISSN:0141-3910. (Elsevier Science Ltd.)
    The drying and oxidative degrdn. of linseed oil have been investigated through exposition of samples in form of thin films to indoor lab. conditions, or treated at a const. temp. of 80°C, or with irradn. at wavelengths > 295 mm. Structure and property changes resulted almost independent of the different treatments and were followed by FTIR spectra, TGA, DSC, insols. detn.- and size-exclusion chromatog. The initial phase of drying consists of the autoxidn. phenomenon of the unsatd. fatty acid components with the development of extensive crosslinking, together with formation of conjugated unsatns. The following stage of slow consumption of labile crosslinks gives rise to a highly stable network, which contains small amts. of low mol. wt. mols., either formed by fragmentation or still present as unreacted triglycerides. The oxidative degrdn. of linseed oil consists of the continuation of the hardening process, and only after long periods of artificial ageing, corresponding to years of natural ageing, the oxidn. also takes place on the alkyl segments, leading to partial fragmentation of the structure.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXksFekt78%253D&md5=847e4ff23473f2eb4ea3e1b4527156c1
  9. 9
    Boon, J. J.; Peulvé, S.; van den Brink, O. F.; Duursma, M. C.; Rainford, D. In Molecular Aspects of Mobile and Stationary Phases in Aging Tempera and Oil Paint Films. Early Italian Paintings Techniques and Analysis, Symposium, Maastricht; Bakkenist, T., Hoppenbrouwers, R., Dubois, H., Eds.; Limburg Conservation Institute: Maastricht, 1996; pp 35– 56.
    Google Scholar
    There is no corresponding record for this reference.
  10. 10
    Bonaduce, I.; Duce, C.; Lluveras-Tenorio, A.; Lee, J.; Ormsby, B.; Burnstock, A.; van den Berg, K. J. Conservation Issues of Modern Oil Paintings: A Molecular Model on Paint Curing. Acc. Chem. Res. 2019, 52, 3397– 3406,  DOI: 10.1021/acs.accounts.9b00296
    Google Scholar
    10
    Conservation Issues of Modern Oil Paintings: A Molecular Model on Paint Curing
    Bonaduce, Ilaria; Duce, Celia; Lluveras-Tenorio, Anna; Lee, Judith; Ormsby, Bronwyn; Burnstock, Aviva; van den Berg, Klaas Jan
    Accounts of Chemical Research (2019), 52 (12), 3397-3406CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)
    Conspectus: The 20th and 21st century oil paintings are presenting a range of challenging conservation problems that can be distinctly different from those noted in paintings from previous centuries. These include the formation of vulnerable surface "skins" of medium and exudates on paint surfaces, efflorescence, unpredictable water and solvent sensitivity, and incidence of paint dripping which can occur within a few years after the paintings were completed. Physicochem. studies of modern oil paints and paintings in recent years have identified a range of possible causal factors for the noted sensitivity of painting surfaces to water and protic solvents, including the formation of water-sol. inorg. salts and/or the accumulation of diacids at the paint surface, which are oxidn. products of the oil binder. Other studies have investigated the relationship between water sensitivity and the degree of hydrolysis of the binder, the proportions of free fatty and dicarboxylic acids formed, as well as the relative content of free metal soaps. Thus far, data indicate that the qual. and quant. compn. of the nonpolymd. fractions of the oil binder cannot be solely or directly related to the solvent sensitivity of the paint film. Conclusions therefore indicate that the polymeric network, formed upon the curing of the oil, plays a fundamental role, suggesting that water sensitivity, at least in some cases, may be related to the poor development and/or polar nature of the formed polymeric network rather than the compn. of the nonpolymd. fractions. Poorly developed polymeric networks, in combination with the migration of polar fractions, i.e., dicarboxylic and hydroxylated fatty acids toward the paint surface, can be related to other degrdn. phenomena, including the sepn. and migration of the paint binder which can lead to the presence of observable skins of medium as well as the more alarming phenomenon of liquefying or dripping oil paints. It is thus crucial to understand the mol. compn. of these paints and their physicochem. behavior to aid the further development of appropriate conservation and preservation strategies, as the risks currently assocd. with surface cleaning treatments and other conservation procedures can be unacceptably high. This Account reviews the relationships between the degrdn. phenomena assocd. with modern oil paintings and the chem. compn. of the oil binder and proposes a mol. model for the development of water sensitivity and other noted degrdn. phenomena. It is suggested that water sensitivity (and possibly other degrdn. phenomena) is a consequence of processes that take place upon curing, and in particular to the rate of formation and decompn. of alkoxyl and peroxyl radicals. These reactions are strongly dependent on the type of oil present, the ambient environmental conditions, and the chem. and phys. nature of the pigments and additives present in the paint formulation. When the curing environment is oxidizing, the chem. of peroxyl radicals dominates the reaction pathways, and oxidative decompn. of the paint film overwhelms crosslinking reactions.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXitFOhsrvP&md5=3308e1d4d201db6219076e74b4d85820
  11. 11
    Bayliss, S.; van den Berg, K. J.; Burnstock, A.; de Groot, S.; van Keulen, H.; Sawicka, A. An investigation into the separation and migration of oil in paintings by Erik Oldenhof. Microchem. J. 2016, 124, 974– 982,  DOI: 10.1016/j.microc.2015.07.015
    Google Scholar
    11
    An investigation into the separation and migration of oil in paintings by Erik Oldenhof
    Bayliss, Sarah; van den Berg, Klaas Jan; Burnstock, Aviva; de Groot, Suzan; van Keulen, Henk; Sawicka, Alysia
    Microchemical Journal (2016), 124 (), 974-982CODEN: MICJAN; ISSN:0026-265X. (Elsevier B.V.)
    The observation of disfiguring yellow oil-like material on the surface of paintings by the contemporary Dutch artist Erik Oldenhof led to an investigation of the material and environmental factors causing the migration and surface deposition of the exudate. A combination of material anal., the examn. of artificially aged reconstructions and information provided by the artist and paint manufacturer, Royal Talens, provided evidence that the phenomenon is related to the drying properties of the safflower oil used, the artist's use of thick paint layers and the availability of light while the paint is drying. Reconstructions demonstrated that the exudation phenomenon can be reproduced and is not restricted to one particular range of oil paint or manufacturer. Visual characteristics of the exudate, including its appearance in UV light and SEM back-scattered images, were documented, and the org. and inorg. components of the paint were characterised by SEM-EDX, XRF, THM-PyGC-MS and FTIR. Results confirmed that the exudate is composed of safflower oil derived from the paint binding medium, and that a difference in P/S ratio between the exudate and paint bulk is due to the presence of metal stearates in the paint that have not migrated to the surface.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXht12gur3N&md5=4067b91770c75ddd2d889cbd175af7d6
  12. 12
    Schaich, K. M. Lipid Oxidation: Theoretical Aspects. In Bailey’s Industrial Oil and Fat Products, 6 ed.; Shahidi, F., Ed.; Wiley, 2005; Vol. 1.
    Google Scholar
    There is no corresponding record for this reference.
  13. 13
    Schaich, K. M. Challenges in Elucidating Lipid Oxidation Mechanisms: When, Where, and How Do Products Arise? In Lipid Oxidation; Logan, A., Nienaber, U., Pan, X., Eds.; AOCS Press, 2013; pp 1– 52.
    Google Scholar
    There is no corresponding record for this reference.
  14. 14
    Schaich, K. M. Lipid Oxidation: New Perspectives on an Old Reaction. In Bailey’s Industrial Oil and Fat Products, 7a ed.; Shahidi, F., Ed.; Wiley, 2020; Vol. 1, pp 1– 72.
    Google Scholar
    There is no corresponding record for this reference.
  15. 15
    Choe, E.; Min, D. B. Chemistry and Reactions of Reactive Oxygen Species in Foods. Crit. Rev. Food Sci. Nutr. 2006, 46, 1– 22,  DOI: 10.1080/10408390500455474
    Google Scholar
    15
    Chemistry and reactions of reactive oxygen species in foods
    Choe, Eunok; Min, David B.
    Critical Reviews in Food Science and Nutrition (2006), 46 (1), 1-22CODEN: CRFND6; ISSN:1040-8398. (Taylor & Francis, Inc.)
    A review. Reactive oxygen species (ROS) are formed enzymically, chem., photochem., and by irradn. of food. They are also formed by the decompn. and the inter-reactions of ROS. Hydroxy radical is the most reactive ROS, followed by singlet oxygen. Reactions of ROS with food components produce undesirable volatile compds. and carcinogens, destroy essential nutrients, and change the functionalities of proteins, lipids, and carbohydrates. Lipid oxidn. by ROS produces low mol. volatile aldehydes, alcs., and hydrocarbons. ROS causes crosslink or cleavage of proteins and produces low mol. carbonyls from carbohydrates. Vitamins are easily oxidized by ROS, esp. singlet oxygen. The singlet oxygen reaction rate was the highest in ss-carotene, followed by tocopherol, riboflavin, vitamin D, and ascorbic acid.
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  16. 16
    Chang, C.; Wu, G.; Zhang, H.; Jin, Q.; Wang, X. Deep-fried flavor: characteristics, formation mechanisms, and influencing factors. Crit. Rev. Food Sci. Nutr. 2020, 60, 1496– 1514,  DOI: 10.1080/10408398.2019.1575792
    Google Scholar
    16
    Deep-fried flavor: characteristics, formation mechanisms, and influencing factors
    Chang, Chang; Wu, Gangcheng; Zhang, Hui; Jin, Qingzhe; Wang, Xingguo
    Critical Reviews in Food Science and Nutrition (2020), 60 (9), 1496-1514CODEN: CRFND6; ISSN:1040-8398. (Taylor & Francis, Inc.)
    A review. Deep-fried flavor, involving fatty, sweet, burnt, and grilled odors, is an important factor leading to the popularity of deep-fried foods. Comparing with flavors from other conventional and innovative thermal treatments, deep-fried flavor is characterized by a rich variety of volatile species (e.g. aldehydes, alcs., ketones, hydrocarbons, carboxylic acids, furans, pyrazines, and pyridines), intricate formation mechanisms, and a stronger attraction to consumers. By means of comprehensively literature research, this article critically reviews deep-fried flavor deriving from lipid oxidn., Maillard reaction, hydrolysis and amino acid degrdn., with a special emphasis to discuss the involvement of lipid oxidn. products in the Maillard pathway to form fried volatiles via secondary processes (e.g. fragmentation, rearrangement, and degrdn.). The reactions are interacted and influenced by various factors, such as frying oils (e.g. fatty acid compn. and oil type), food components (e.g. amino acid and sugar), frying conditions (e.g. oxygen concn., frying time, temp., pH, and moisture content), and frying types (e.g. vacuum frying and air frying). Overall, well understanding of chem. origins of deep-fried volatiles is meaningful to economically manipulate the frying process, optimize the fried flavor, and improve the safety and consumer acceptance of deep-fried foods.
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  17. 17
    Guéraud, F.; Atalay, M.; Bresgen, N.; Cipak, A.; Eckl, P. M.; Huc, L.; Jouanin, I.; Siems, W.; Uchida, K. Chemistry and biochemistry of lipid peroxidation products. Free Radical Res. 2010, 44, 1098– 1124,  DOI: 10.3109/10715762.2010.498477
    Google Scholar
    17
    Chemistry and biochemistry of lipid peroxidation products
    Gueraud, F.; Atalay, M.; Bresgen, N.; Cipak, A.; Eckl, P. M.; Huc, L.; Jouanin, I.; Siems, W.; Uchida, K.
    Free Radical Research (2010), 44 (10), 1098-1124CODEN: FRARER; ISSN:1071-5762. (Informa Healthcare)
    A review. Oxidative stress and resulting lipid peroxidn. is involved in various and numerous pathol. states including inflammation, atherosclerosis, neurodegenerative diseases and cancer. This review is focused on recent advances concerning the formation, metab. and reactivity towards macromols. of lipid peroxidn. breakdown products, some of which being considered as second messengers' of oxidative stress. This review relates also new advances regarding apoptosis induction, survival/proliferation processes and autophagy regulated by 4-hydroxynonenal, a major product of omega-6 fatty acid peroxidn., in relationship with detoxication mechanisms. The use of these lipid peroxidn. products as oxidative stress/lipid peroxidn. biomarkers is also addressed.
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  18. 18
    Cheeseman, K. H.; Slater, T. F. An introduction to free radical biochemistry. Br. Med. Bull. 1993, 49, 481– 493,  DOI: 10.1093/oxfordjournals.bmb.a072625
    Google Scholar
    18
    An introduction to free radical biochemistry
    Cheeseman, K. H.; Slater, T. F.
    British Medical Bulletin (1993), 49 (3), 481-93CODEN: BMBUAQ; ISSN:0007-1420.
    A review with 42 refs. Oxygen free radicals and reactive oxygen species, prodn. of free radicals in cells, damaging reactions of free radicals, defences against free radicals, and free radicals in human disease were discussed.
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  19. 19
    Hage, R.; de Boer, J. W.; Maaijen, K. Manganese and Iron Catalysts in Alkyd Paints and Coatings. Inorganics 2016, 4, 11,  DOI: 10.3390/inorganics4020011
    Google Scholar
    19
    Manganese and iron catalysts in alkyd paints and coatings
    Hage, Ronald; De Boer, Johannes W.; Maaijen, Karin
    Inorganics (2016), 4 (2), 11/1-11/18CODEN: INORCW; ISSN:2304-6740. (MDPI AG)
    A review. Many paint, ink and coating formulations contain alkyd-based resins which cure via autoxidn. mechanisms. While cobalt-soaps have been used for many decades, there is a continuing and accelerating desire by paint companies to develop alternatives for the cobalt soaps, due to likely classification as carcinogens under the REACH (Registration, Evaluation, Authorisation and Restriction of Chems.) legislation. Alternative driers, for example manganese and iron soaps, have been applied for this purpose. However, relatively poor curing capabilities make it necessary to increase the level of metal salts to such a level that often coloring of the paint formulation occurs. More recent developments include the application of manganese and iron complexes with a variety of org. ligands. This review will discuss the chem. of alkyd resin curing, the applications and reactions of cobalt-soaps as curing agents, and, subsequently, the paint drying aspects and mechanisms of (model) alkyd curing using manganese and iron catalysts.
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  20. 20
    Vangorkum, R.; Bouwman, E. The oxidative drying of alkyd paint catalysed by metal complexes. Coord. Chem. Rev. 2005, 249, 1709– 1728,  DOI: 10.1016/j.ccr.2005.02.002
    Google Scholar
    There is no corresponding record for this reference.
  21. 21
    Soucek, M. D.; Khattab, T.; Wu, J. Review of autoxidation and driers. Prog. Org. Coat. 2012, 73, 435– 454,  DOI: 10.1016/j.porgcoat.2011.08.021
    Google Scholar
    21
    Review of autoxidation and driers
    Soucek, M. D.; Khattab, T.; Wu, J.
    Progress in Organic Coatings (2012), 73 (4), 435-454CODEN: POGCAT; ISSN:0300-9440. (Elsevier B.V.)
    A review. This article is an overview of the chem. and driers used in autoxidatively cured coatings and in particular alkyds. The drying process for alkyds and other unsatd. fatty acid materials is based on a series of chem. reactions known as autoxidn. The autoxidative process is usually catalyzed by metal salts known as driers. Numerous of investigations have elucidated the catalytic activity and reaction mechanism of the drying process. Spectroscopic techniques, esp. mass spectrometry, have been used to study the autoxidn. process and its products. Recent investigations on the oxidative drying of alkyd coating films are presented with a focus on both metal based and more environmental friendly means of catalysis.
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  22. 22
    Baij, L.; Chassouant, L.; Hermans, J. J.; Keune, K.; Iedema, P. D. The concentration and origins of carboxylic acid groups in oil paint. RSC Adv. 2019, 9, 35559– 35564,  DOI: 10.1039/c9ra06776k
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    22
    The concentration and origins of carboxylic acid groups in oil paint
    Baij, Lambert; Chassouant, Louise; Hermans, Joen J.; Keune, Katrien; Iedema, Piet D.
    RSC Advances (2019), 9 (61), 35559-35564CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)
    Although the concn. of carboxylic acid (COOH) groups is crucial to understand oil paint chem., anal. challenges hindered COOH quantification in complex polymerised oil samples thus far. The concn. of COOH groups is important in understanding oil paint degrdn. because it drives the breakdown of reactive inorg. pigments to dissolve in the oil network and form metal carboxylates. The metal ions in such an ionomeric polymer network can exchange with satd. fatty acids to form cryst. metal soaps (metal complexes of satd. fatty acids), leading to serious problems in many paintings worldwide. We developed two methods based on ATR-FTIR spectroscopy to accurately est. the COOH concn. in artificially aged oil paint models. Using tailored model systems composed of linseed oil, ZnO and inert filler pigments, these dried oil paints were found to contain one COOH group per triacylglycerol unit. Model systems based on a mixt. of long chain alcs. showed that the calcd. COOH concn. originates from side chain autoxidn. at low relative humidity (RH). The influence of increasing RH and ZnO concn. on COOH formation was studied and high relative humidity conditions were shown to promote the formation of COOH groups. No significant ester hydrolysis was found under the conditions studied. Our results show the potential of quant. anal. of oil paint model systems for aiding careful (re)evaluation of conservation strategies.
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  23. 23
    Bronken, I. A. T.; Boon, J. J. Hard dry paint, softening tacky paint, and exuding drips on composition (1952) by Jean-Paul Riopelle. Issues in Contemporary Oil Paint; Springer, 2014; pp 247– 262.
    Google Scholar
    There is no corresponding record for this reference.
  24. 24
    Erhardt, D.; Tumosa, C. S.; Mecklenburg, M. F. Long-term chemical and physical processes in oil paint films. Stud. Conserv. 2005, 50, 143– 150,  DOI: 10.1179/sic.2005.50.2.143
    Google Scholar
    There is no corresponding record for this reference.
  25. 25
    La Nasa, J.; Lee, J.; Degano, I.; Burnstock, A.; van den Berg, K. J.; Ormsby, B.; Bonaduce, I. The role of the polymeric network in the water sensitivity of modern oil paints. Sci. Rep. 2019, 9, 3467,  DOI: 10.1038/s41598-019-39963-z
    Google Scholar
    25
    The role of the polymeric network in the water sensitivity of modern oil paints
    La Nasa Jacopo; Degano Ilaria; Bonaduce Ilaria; Lee Judith; Ormsby Bronwyn; Burnstock Aviva; van den Berg Klaas Jan
    Scientific reports (2019), 9 (1), 3467 ISSN:.
    Spectroscopic and mass spectrometric analytical techniques were used to characterise two naturally aged Winsor & Newton (W&N) Winsor Green (phthalocyanine green, PG7) artists' oil colour paint swatches dating to 1993 and 2003. Infrared and Energy Dispersive X-ray (EDX) analysis indicated that the swatches were of closely similar composition, yet the swatch from 2003 was water-sensitive whilst the swatch from 1993 was not. Water-sensitivity is a conservation challenge associated with significant numbers of modern oil paintings and this study aimed to further develop our understanding of the molecular causes of water sensitivity. SEM elemental mapping of samples taken from both swatches provided no indication for the formation of epsomite - a known cause of water sensitivity in some modern oil paintings. Liquid chromatography coupled with mass spectrometry (HPLC-MS) and gas chromatography coupled with mass spectrometry (GC-MS) also revealed very similar qualitative-quantitative composition in terms of unbound and esterified medium fractions. The polymeric network was investigated using analytical pyrolysis. A combination of flash pyrolysis coupled with gas chromatography mass spectrometry (Py-GC-MS) together with evolved gas analysis mass spectrometry (EGA-MS) revealed that the polymeric material was relatively more abundant in the non-water-sensitive paint. This is the first multi-analytical study that has demonstrated a correlation between water-sensitivity and the degree of polymerisation of the oil medium; independent of other known causes of water-sensitivity.
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  26. 26
    Modugno, F.; Di Gianvincenzo, F.; Degano, I.; van der Werf, I. D.; Bonaduce, I.; van den Berg, K. J. On the influence of relative humidity on the oxidation and hydrolysis of fresh and aged oil paints. Sci. Rep. 2019, 9, 5533,  DOI: 10.1038/s41598-019-41893-9
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    26
    On the influence of relative humidity on the oxidation and hydrolysis of fresh and aged oil paints
    Modugno Francesca; Di Gianvincenzo Fabiana; Degano Ilaria; Bonaduce Ilaria; Di Gianvincenzo Fabiana; van der Werf Inez Dorothe; van den Berg Klaas Jan
    Scientific reports (2019), 9 (1), 5533 ISSN:.
    Modern oil paintings are affected by conservation issues related to the oil paint formulations and to the fact that they are often unvarnished, and in direct contact with the environment. Understanding the evolution of the molecular composition of modern oil paint during ageing, under the influence of environmental factors, is fundamental for a better knowledge of degradation phenomena and risk factors affecting modern art. We investigated for the first time the influence of relative humidity on the chemical composition of modern oil paints during curing and artificial ageing. For this purpose, modern oil paint layers naturally aged for 10 years were further artificially aged in low and high relative humidity conditions. Moreover, the influence of RH% on the curing of fresh paint layers was studied. The paints used in the experiments are from three suppliers (Old Holland, Winsor&Newton, and Talens), and contain cadmium or cadmium zinc sulfide as main pigment. The changes in the composition of extracts of paint samples were investigated by direct electrospray mass spectrometry with a quadrupole-time of flight mass analyser (ESI-Q-ToF). The obtained mass spectral data were interpreted by means of principal component analysis (PCA) operated on a data set containing the relative abundance of ions associated to significant molecules present in the extracts, and also by calculating the ratios between the signals relative to fatty acids, dicarboxylic acids and acylglycerols, related to hydrolysis and oxidation phenomena. The same paint samples were also analysed, in bulk, by pyrolysis gas chromatography mass spectrometry (Py-GC/MS), achieving chemical information on the total lipid fraction. High performance liquid chromatography (HPLC) ESI-Q-ToF was carried out for the characterisation of the profile of free fatty acids (FFA) and acylglycerols, defining the nature of the oils used in the paint formulations, and for the determination of the degree of hydrolysis. This study demonstrated that relative humidity conditions significantly influence the chemical composition of the paints. Ageing under high RH% conditions produced an increase of the formation of dicarboxylic acids compared to ageing under low RH%, for all paints, in addition to a higher degree of hydrolysis, followed by evaporation of free fatty acids.
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  27. 27
    Tumosa, C. S.; Mecklenburg, M. F. Weight Changes on Oxidation of Drying and Semi-drying Oils, Collection Forum , 2003.
    Google Scholar
    There is no corresponding record for this reference.
  28. 28
    Tumosa, C. S.; Mecklenburg, M. F. The influence of lead ions on the drying of oils. Stud. Conserv. 2005, 50, 39– 47,  DOI: 10.1179/sic.2005.50.supplement-1.39
    Google Scholar
    There is no corresponding record for this reference.
  29. 29
    Van den Berg, K. J.; Bonaduce, I.; Burnstock, A.; Ormsby, B.; Scharff, M.; Carlyle, L.; Heydenreich, G.; Keune, K. Conservation of Modern Oil Paintings; Springer, 2019.
    Google Scholar
    There is no corresponding record for this reference.
  30. 30
    Van den Berg, K. J.; Burnstock, A.; De Keijzer, M.; Krueger, J.; Learner, T.; De Tagle, A.; Heydenreich, G. Issues in Contemporary Oil Paint; Springer, 2014.
    Google Scholar
    There is no corresponding record for this reference.
  31. 31
    Boon, J. J.; Hoogland, F. G. Investigating fluidizing dripping pink commercial paint on Van Hemert’s Seven-series works from 1990–1995. Issues in Contemporary Oil Paint; Springer, 2014; pp 227– 246.
    Google Scholar
    There is no corresponding record for this reference.
  32. 32
    Lee, J.; Bonaduce, I.; Modugno, F.; La Nasa, J.; Ormsby, B.; van den Berg, K. J. Scientific investigation into the water sensitivity of twentieth century oil paints. Microchem. J. 2018, 138, 282– 295,  DOI: 10.1016/j.microc.2018.01.017
    Google Scholar
    32
    Scientific investigation into the water sensitivity of twentieth century oil paints
    Lee, Judith; Bonaduce, Ilaria; Modugno, Francesca; La Nasa, Jacopo; Ormsby, Bronwyn; van den Berg, Klaas Jan
    Microchemical Journal (2018), 138 (), 282-295CODEN: MICJAN; ISSN:0026-265X. (Elsevier B.V.)
    In order to develop a better understanding at the mol. level of water sensitivity in twentieth century oil paintings, water sensitive Winsor & Newton oil paint swatches and twentieth century oil paintings were characterised using gas chromatog.-mass spectrometry (GC-MS) and direct injection electrospray ionisation mass spectrometry (ESI-MS), and the data were analyzed using principal component anal. Liq. chromatog. coupled with tandem mass spectrometry based on quadrupole and time of flight mass detectors and electrospray interface (HPLC-ESI-Q-ToF) was also used to obtain a better insight into the mol. compn. of a selection of samples. The study highlights a strong relationship between the mol. compn. of the binding medium and the type of pigment present in the paint, which relates to water sensitivity. Consistently non-water sensitive lead white, titanium white, and zinc white paints [all contg. zinc oxide] contained a relatively low proportion of extractable diacids, and a relatively high proportion of extractable short chain monoacids. These paints also contained a relatively low level of unsatd. and hydroxylated glycerides. Water sensitive iron oxide and ultramarine paints are assocd. with both a relatively high degree of oxidn. and a high proportion of extractable diacids, as well as a relatively high content of unsatd. and hydroxylated glycerides. Water sensitive cadmium red, yellow and orange paints were generally not highly oxidised, but they also contained a relatively high content of unsatd. and hydroxylated glycerides. It is hypothesised that water sensitivity relates to a low degree of sapon. and crosslinking and possibly, on the relative content of dicarboxylic acids.
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  33. 33
    Fuster-López, L.; Izzo, F. C.; Piovesan, M.; Yusá-Marco, D. J.; Sperni, L.; Zendri, E. Study of the chemical composition and the mechanical behaviour of 20th century commercial artists’ oil paints containing manganese-based pigments. Microchem. J. 2016, 124, 962– 973,  DOI: 10.1016/j.microc.2015.08.023
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    33
    Study of the chemical composition and the mechanical behaviour of 20th century commercial artists' oil paints containing manganese-based pigments
    Fuster-Lopez, Laura; Izzo, Francesca Caterina; Piovesan, Marco; Yusa-Marco, Dolores J.; Sperni, Laura; Zendri, Elisabetta
    Microchemical Journal (2016), 124 (), 962-973CODEN: MICJAN; ISSN:0026-265X. (Elsevier B.V.)
    The present study deals with 20th century manufd. artists' oil paints contg. raw and burnt umber pigments, this is, natural earth pigments resulting from the combination of iron and manganese oxides. Manganese, in particular, is known to be a primary drier and to have a siccative effect on oil paint films. This research aims to show the diversity of formulations behind apparently same com. names, as well as to understand how the content of manganese, the presence of modern lipidic media and the hydrolysis mechanisms can promote significant differences in the expected mech. properties of oil paint films, thus conditioning their long-term performance. Several manufd. artists' oil paint films contg. manganese were selected. Dried films from raw and burnt umber oil paints by Winsor&Newton (UK), Grumbacher (USA), Gamblin (USA) and Speedball (USA) were studied and information about their chem. compn. and mech. behavior is here presented. In addn. to the identification and the study of the inorg. and org. components present in each formulation through LM, SEM-EDX, FTIR-ATR, XRD, GC-MS anal., tensile tests were run and stress-strain curves were obtained. Together with evident hue differences, the obtained results showed significant differences in the chem. compn. and the mech. behavior of the oil paint films.
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  34. 34
    Artesani, A. Zinc oxide instability in drying oil paint. Mater. Chem. Phys. 2020, 255, 123640,  DOI: 10.1016/j.matchemphys.2020.123640
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    34
    Zinc oxide instability in drying oil paint
    Artesani, Alessia
    Materials Chemistry and Physics (2020), 255 (), 123640CODEN: MCHPDR; ISSN:0254-0584. (Elsevier B.V.)
    In this work, we review recent studies on zinc sapon. mechanisms, which occur as degrdn. products in modern oil paintings and severely affect the cohesion of pictorial layers. The issue has gained great attention in the last decades, when research moved from the mere phenomenon observation to the understating of the crit. behavior of zinc oxide in an oleic matrix. The structure formed by the two paint constituents, i.e. drying oil (polymeric matrix) and pigment (suspended solid particles), demonstrated to represent a fundamental aspect for the instability of the paint film and its ageing showed important analogies with degrdn. of com. ionomer networks. The complexity of the system and the cultural value of the investigated objects has posed great challenges and has required the collaboration between physicists, chemists and conservation scientists to answer both applied and fundamental questions related to this conservative issue. As the research has now reached maturity, this review conveys the acquired knowledge on this topic, summarizing and illustrating the main phases of evolution of the zinc oxide-binder system, corresponding to pigment dispersion and dissoln., formation of the ionomer network and crystn. of metal soaps. The final scope of this work is to guide and pave the way for future studies related to this issue and facing similar problematics.
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  35. 35
    Burnstock, A.; van den Berg, K. J.; de Groot, S.; Wijnberg, L. An investigation of water-sensitive oil paints in twentieth-century paintings. Modern Paints Uncovered, London; Getty Conservation Institute London, 2006; pp 177– 188.
    Google Scholar
    There is no corresponding record for this reference.
  36. 36
    de la Rie, E. R.; Michelin, A.; Ngako, M.; Del Federico, E.; Del Grosso, C. Photo-catalytic degradation of binding media of ultramarine blue containing paint layers: A new perspective on the phenomenon of ″ultramarine disease″ in paintings. Polym. Degrad. Stab. 2017, 144, 43– 52,  DOI: 10.1016/j.polymdegradstab.2017.08.002
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    36
    Photo-catalytic degradation of binding media of ultramarine blue containing paint layers: A new perspective on the phenomenon of "ultramarine disease" in paintings
    de la Rie, E. Rene; Michelin, Anne; Ngako, Manuela; Del Federico, Eleonora; Del Grosso, Chelsey
    Polymer Degradation and Stability (2017), 144 (), 43-52CODEN: PDSTDW; ISSN:0141-3910. (Elsevier Ltd.)
    Failure of ultramarine blue paint layers in historic as well as modern paintings has been reported in the literature many times and is often referred to as "ultramarine disease" or "ultramarine sickness.". The pigment itself is known to degrade hydrolytically when exposed to acids, but whether this is the primary cause of the failure remains unclear. This paper describes a study in which ultramarine blue paints using linseed oil and a urea-aldehyde resin as binding media were aged under simulated indoor conditions. The paints were analyzed using reflectance spectroscopy, SEM, and Raman and NMR spectroscopy. The urea-aldehyde resin binding medium was analyzed using size exclusion chromatog. and Fourier-transform IR spectroscopy. The study provides evidence of photo-catalytic degrdn. of binding media of ultramarine blue paint layers via free-radical processes, causing changes in reflectance while the pigment itself remains intact. It is believed that this is the primary process behind the degrdn. of ultramarine blue paint layers in paintings.
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  37. 37
    Hermans, J. J.; Keune, K.; van Loon, A.; Corkery, R. W.; Iedema, P. D. Ionomer-like structure in mature oil paint binding media. RSC Adv. 2016, 6, 93363– 93369,  DOI: 10.1039/c6ra18267d
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    37
    Ionomer-like structure in mature oil paint binding media
    Hermans, Joen J.; Keune, Katrien; van Loon, Annelies; Corkery, Robert W.; Iedema, Piet D.
    RSC Advances (2016), 6 (96), 93363-93369CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)
    IR spectra of samples from oil paintings often show metal carboxylate bands that are broader and shifted compared to those of cryst. metal soap stds. (metal complexes of long-chain satd. fatty acids). Using quant. attenuated total reflection Fourier transform IR spectroscopy (ATR-FTIR), it is demonstrated that the broad metal carboxylate band is typically too intense to be explained by carboxylates adsorbed on the surface of pigment particles or disordered metal complexes of satd. fatty acids. The metal carboxylate species assocd. with the broad bands must therefore be an integral part of the polymd. binding medium. Small-angle X-ray scattering (SAXS) measurements on model ionomer systems based on linseed oil revealed that the medium contains ionic clusters similar to more classical ionomers. These structural similarities are very helpful in understanding the chem. of mature oil paint binding media and the potential degrdn. mechanisms that affect oil paintings.
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  38. 38
    Silvester, G.; Burnstock, A.; Megens, L.; Learner, T.; Chiari, G.; van den Berg, K. J. A cause of water-sensitivity in modern oil paint films: the formation of magnesium sulphate. Stud. Conserv. 2014, 59, 38– 51,  DOI: 10.1179/2047058413y.0000000085
    Google Scholar
    38
    A cause of water-sensitivity in modern oil paint films: The formation of magnesium sulphate
    Silvester, Genevieve; Burnstock, Aviva; Megens, Luc; Learner, Tom; Chiari, Giacomo; van den Berg, Klaas Jan
    Studies in Conservation (2014), 59 (1), 38-51CODEN: SCONAH; ISSN:0039-3630. (Maney Publishing)
    Unvarnished twentieth-century oil paintings are often sensitive to aq. swabbing, a method routinely employed by conservators for surface cleaning. This study proposes a connection between sensitivity and the presence of magnesium sulfate heptahydrate which has been identified on the surface of some of water-sensitive paintings. The probable source of magnesium is magnesium carbonate, an additive in some twentieth-century oil paints, which has reacted with atm. sulfur dioxide (SO2). Films made using modern manufd. paints and formulations made in the lab. were exposed to gaseous SO2 and raised relative humidity and examd. using SEM with energy dispersive X-ray spectroscopy and X-ray diffraction to characterize the cryst. entities. Films contg. magnesium carbonate formed magnesium sulphite and sulfate hydrates. Films contg. zinc oxide were also investigated. These formed zinc and sulfur contg. salts. Sensitivity to swabbing with water before and after exposure was evaluated. Films that developed salts, demonstrated increased sensitivity to aq. swabbing after exposure to SO2. Findings suggest that increased water sensitivity may be due to a combination of the formation of hygroscopic degrdn. products and to weakening of the paint film due to salt-induced disruption of the surface.
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  39. 39
    Zumbühl, S. The Rate of Solvent Action on Modern Oil Paint. Conservation of Modern Oil Paintings; Springer, 2019; pp 465– 474.
    Google Scholar
    There is no corresponding record for this reference.
  40. 40
    Sutherland, K. Solvent-extractable components of linseed oil paint films. Stud. Conserv. 2003, 48, 111– 135,  DOI: 10.1179/sic.2003.48.2.111
    Google Scholar
    40
    Solvent-extractable components of linseed oil paint films
    Sutherland, Ken
    Studies in Conservation (2003), 48 (2), 111-135CODEN: SCONAH; ISSN:0039-3630. (International Institute for Conservation of Historic and Artistic Works)
    As part of an investigation into the risks assocd. with the exposure of oil paintings to org. solvents in cleaning and other conservation treatments, the extn. of sol. org. components from a variety of pigmented oil films was studied. The extractable material was characterized using chromatog. anal. of extractable fatty acids. The influence on the leaching process of factors such as pigmentation and age of the paint films, and the type of solvent treatment, was examd. In addn. to lab.-prepd. paint films from three to 65 yr old, samples from paintings dating from as early as the thirteenth century were analyzed, to enable the data from the younger test films to be put in a more practical context. Expts. to measure the extent of leaching resulting from simulated cleaning treatments on paintings dating from the seventeenth to nineteenth centuries are also reported.
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  41. 41
    Astefanei, A.; van den Berg, K. J.; Burnstock, A.; Corthals, G. Surface Acoustic Wave Nebulization-Mass Spectrometry as a New Tool to Investigate the Water Sensitivity Behavior of 20th Century Oil Paints. J. Am. Soc. Mass Spectrom. 2021, 32, 444– 454,  DOI: 10.1021/jasms.0c00272
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    41
    Surface Acoustic Wave Nebulization-Mass Spectrometry as a New Tool to Investigate the Water Sensitivity Behavior of 20th Century Oil Paints
    Astefanei, Alina; van den Berg, Klaas Jan; Burnstock, Aviva; Corthals, Garry
    Journal of the American Society for Mass Spectrometry (2021), 32 (2), 444-454CODEN: JAMSEF; ISSN:1879-1123. (American Chemical Society)
    The sensitive surfaces of many unvarnished 20th century oil paintings are of great concern for conservators and collection keepers. They may show degrdn. problems such as paint delamination, dripping, and soft and sticky paint and pose challenges for cleaning due to solvent sensitivity. We report for the first time the use of an innovative ambient ionization technique, surface acoustic wave nebulization-mass spectrometry (SAWN-MS), for the identification and characterization of fatty acids, dicarboxylic species and glycerides in water-sensitive modern oil paints. The compn. of 10 relevant Winsor and Newton 1964-1965 paint swatches that present different degrees of water sensitivity and two paint samples from a painting by the British artist Francis Bacon were studied. Principal component anal. was used for SAWN-MS data classification. Electrospray ionization (ESI)-MS was used as control method, specifically to compare the obtained ratios of markers of interest by the two ionization techniques. The results obtained by both ESI-MS and SAWN-MS are correlated and discussed in a broader context including the information on the oil media obtained by gas chromatog. (GC-MS) and also on the inorg. materials and salts characterized using a combination of methods in previous reports on samples from the same manufacturer. SAWN-MS was found to be a suitable tool for the detn. of sol. org. constituents present in the paints. The method provides an indication of the level of oxidn. and hydrolysis of the paint film by monitoring specific markers such as free palmitic and stearic acids, azelaic acid, monoacylglycerols, and diacylglycerols. The data showed that a higher level of water sensitivity coupled with a high level of oxidn. and hydrolysis is linked to higher dicarboxylic acid, diacyl- and triacylglyceride content and lower levels of short chain fatty acids. The data obtained by SAWN-MS provided a good correlation between the monitored species and the degree of water sensitivity.
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  42. 42
    Mayer, R. Artist’s Handbook of Materials and Techniques: Revised and Updated; Viking Books, 1991.
    Google Scholar
    There is no corresponding record for this reference.
  43. 43
    Roy, A. Artists’ Pigments. A Handbook of Their History and Characteristics; Archetype Publications Ltd., London, 1993; Vol. 2.
    Google Scholar
    There is no corresponding record for this reference.
  44. 44
    Harley, R. D. Artists’ Pigments, c. 1600–1835, a study in English documentary sources; Camelot Press, 1982.
    Google Scholar
    There is no corresponding record for this reference.
  45. 45
    Boon, J. J.; Hoogland, F.; Keune, K.; Parkin, H. M. Chemical processes in aged oil paints affecting metal soap migration and aggregation. AIC Paintings Specialty Group Postprints, Providence, Rhode Island , June 16–19, 2006; Vol. 19, pp 16– 23.
    Google Scholar
    There is no corresponding record for this reference.
  46. 46
    White, R. E.; Thomas, P. S.; Phillips, M. R.; Wuhrer, R. A DSC study of the effect of lead pigments on the drying of cold pressed linseed oil. J. Therm. Anal. Calorim. 2005, 80, 237– 239,  DOI: 10.1007/s10973-005-0642-5
    Google Scholar
    46
    A DSC study of the effect of lead pigments on the drying of cold pressed linseed oil
    White, R. E.; Thomas, P. S.; Phillips, M. R.; Wuhrer, R.
    Journal of Thermal Analysis and Calorimetry (2005), 80 (1), 237-239CODEN: JTACF7; ISSN:1388-6150. (Springer)
    Cold pressed linseed oil and paints prepd. using the inorg. pigments; lead white and red lead, were characterized using non-isothermal differential scanning calorimetry (DSC) in an air atm. to det. the effect of the pigment on the oxidative polymn. of the drying oil medium. For each paint sample, the onset temp. for oxidn. was reduced from 166° to the range 50 to 60° when a heating rate of 5 K min-1 was used. In order to det. the rate of drying, the non-isothermal expts. were carried out using a range of heating rates. A change in the mechanism oxidative polymn. was obsd. as the heating rate was increased.
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  47. 47
    Booth, D. G.; Dann, S. E.; Weller, M. T. The effect of the cation composition on the synthesis and properties of ultramarine blue. Dyes Pigm. 2003, 58, 73– 82,  DOI: 10.1016/s0143-7208(03)00037-8
    Google Scholar
    47
    The effect of the cation composition on the synthesis and properties of ultramarine blue
    Booth, D. G.; Dann, S. E.; Weller, M. T.
    Dyes and Pigments (2003), 58 (1), 73-82CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Science Ltd.)
    The effect of potassium cations on the shade of the ultramarine blue pigment system has been investigated by anal. of com. materials, ion exchange reactions of sodium-form ultramarine blue and a detailed study of the effect of adding potassium sources to ultramarine precursor mixts. Incorporation of potassium cations has the result of producing redder shade material, and the replacement of ∼20% of the sodium in the std. reaction mixt. produces the optimized red-shade pigment. The origin of this hue control may be a direct effect, involving interaction of potassium ions with the ultramarine blue structure and the S3- chromophore or, more likely, potassium ions aids the stabilization of S3- within the sodalite framework during the ultramarine blue formation process. In the com. process, the role of the potassium source in red shade formation may be performed by the incorporation of potassium-rich feldspar additives.
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  48. 48
    von Pettenkofer, M. über ölfarbe und Conservirung der GemÄlde-Gallerien durch das Regenerations-Verfahren; Vieweg, 1870.
    Google Scholar
    There is no corresponding record for this reference.
  49. 49
    Schnetz, K.; Gambardella, A. A.; van Elsas, R.; Rosier, J.; Steenwinkel, E. E.; Wallert, A.; Iedema, P. D.; Keune, K. Evidence for the catalytic properties of ultramarine pigment. J. Cult. Herit. 2020, 45, 25– 32,  DOI: 10.1016/j.culher.2020.04.002
    Google Scholar
    There is no corresponding record for this reference.
  50. 50
    Ogbobe, O.; Ossai, N. N. Effect of colour on the mechanical and chemical properties of naturally photooxidized high density polyethylene. Acta Polym. 1992, 43, 173– 176,  DOI: 10.1002/actp.1992.010430308
    Google Scholar
    50
    Effect of color on the mechanical and chemical properties of naturally photooxidized high-density polyethylene
    Ogbobe, O.; Ossai. N. N.
    Acta Polymerica (1992), 43 (3), 173-6CODEN: ACPODY; ISSN:0323-7648.
    The effect of color on the mech. and chem. properties of colored HDPE at photooxidn. by natural sunlight is studied. The extent of polymer deterioration depends on the nature of the applied pigments.
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  51. 51
    Iwu, C. F.; Egbuhuzor, M. Oxidative Photodegradation of Colored LLDPE, ANTEC-Conference Proceedings , 2004; pp 3559– 3563.
    Google Scholar
    There is no corresponding record for this reference.
  52. 52
    Bonaduce, I.; Carlyle, L.; Colombini, M. P.; Duce, C.; Ferrari, C.; Ribechini, E.; Selleri, P.; Tiné, M. R. New Insights into the Ageing of Linseed Oil Paint Binder: A Qualitative and Quantitative Analytical Study. PLoS One 2012, 7, e49333  DOI: 10.1371/journal.pone.0049333
    Google Scholar
    52
    New insights into the ageing of linseed oil paint binder: a qualitative and quantitative analytical study
    Bonaduce, Ilaria; Carlyle, Leslie; Colombini, Maria Perla; Duce, Celia; Ferrari, Carlo; Ribechini, Erika; Selleri, Paola; Tine, Maria Rosaria
    PLoS One (2012), 7 (11), e49333CODEN: POLNCL; ISSN:1932-6203. (Public Library of Science)
    This paper presents an anal. investigation of paint reconstructions prepd. with linseed oil that have undergone typical 19th century treatments in prepn. for painting. The oil was mech. extd. from the same seed lot, which was then processed by various methods: water washing, heat treatments, and the addn. of driers, with and without heat. A modern process lead white (Dutch source, Schoonhoven) and a com. available vine black were used as pigments. The reconstructions were prepd. in 1999, and naturally aged from then onwards. We compared thermogravimetric anal. (TG), which yields macromol. information, with gas chromatog.-mass spectrometry (GC-MS) and direct exposure mass spectrometry (DEMS), which both provide mol. information. The study enabled us to quant. demonstrate, for the first time, that the parameters used to identify drying oils are deeply influenced by the history of the paint. In particular, here we show that the ratio between the relative amts. of palmitic and stearic acid (P/S), which is used as an index for differentiating between drying oils, is extremely dependent on the pigments present and the age of the paint. Moreover the study revealed that neither the P/S parameter nor the ratios between the relative amts. of the various dicarboxylic acids (azelaic over suberic and azelaic over sebacic) can be used to trace the sorts of pre-treatment undergone by the oil investigated in this study. The final results represent an important milestone for the scientific community working in the field, highlighting that further research is still necessary to solve the identification of drying oils in works of art.
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  53. 53
    Bonaduce, I.; Carlyle, L.; Colombini, M. P.; Duce, C.; Ferrari, C.; Ribechini, E.; Selleri, P.; Tiné, M. R. A multi-analytical approach to studying binding media in oil paintings: Characterisation of differently pre-treated linseed oil by DE-MS, TG and GC/MS. J. Therm. Anal. Calorim. 2012, 107, 1055– 1066,  DOI: 10.1007/s10973-011-1586-6
    Google Scholar
    53
    A multi-analytical approach to studying binding media in oil paintings
    Bonaduce, Ilaria; Carlyle, Leslie; Colombini, Maria Perla; Duce, Celia; Ferrari, Carlo; Ribechini, Erika; Selleri, Paola; Tine, Maria Rosaria
    Journal of Thermal Analysis and Calorimetry (2012), 107 (3), 1055-1066CODEN: JTACF7; ISSN:1388-6150. (Akademiai Kiado)
    This article presents a multi-anal. approach to investigating the drying, polymn. and oxidative degrdn. of linseed oil, which had undergone various treatments known to be undertaken during the nineteenth century in prepn. for painting. The oil was mech. extd. from the same seed lot then processed by different methods: water washing, heat treatments, and the addn. of driers, with and without heat. The oil was prepd. in 1999 within the framework of the MOLART project. We compared thermogravimetric anal. (TG), which yields macromol. information, with gas-chromatog. mass-spectrometry (GC/MS) and direct exposure mass spectrometry (DE-MS), which provide mol. information. This comparison enabled us to elucidate the role of pre-treatment on the compn. of the oil. TG and oxygen uptake curves registered at a const. temp. helped us to identify the different phys. behavior of the oil samples, thus highlighting the presence of hydrolyzed, oxidized and crosslinked fractions, as a consequence of the different pre-treatments. GC/MS was used to characterize the sol. and non-polymeric fraction of the oil, to calc. the ratios of palmitic to stearic acid (P/S), and azelaic to palmitic acid (A/P), and to further evaluate the effects of oil pre-treatments. DE-MS using chem. ionization with CH4, enabled us to establish the chem. compn. of the oil in different stages of ageing. DE-MS proved to be a useful tool for a simultaneous semi-quant. characterization of the free fatty acids, monoglycerides, diglycerides and triglycerides present in each sample. The combination of thermal anal. with GC/MS and DE-MS enabled a model to be developed, which unravelled how oil pre-treatments produce binders with different phys.-chem. qualities.
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  54. 54
    Dubrulle, L.; Lebeuf, R.; Thomas, L.; Fressancourt-Collinet, M.; Nardello-Rataj, V. Catalytic activity of primary and secondary driers towards the oxidation and hydroperoxide decomposition steps for the chemical drying of alkyd resin. Prog. Org. Coat. 2017, 104, 141– 151,  DOI: 10.1016/j.porgcoat.2016.12.018
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    54
    Catalytic activity of primary and secondary driers towards the oxidation and hydroperoxide decomposition steps for the chemical drying of alkyd resin
    Dubrulle, L.; Lebeuf, R.; Thomas, L.; Fressancourt-Collinet, M.; Nardello-Rataj, V.
    Progress in Organic Coatings (2017), 104 (), 141-151CODEN: POGCAT; ISSN:0300-9440. (Elsevier B.V.)
    The autoxidn. of fatty acid Me esters (FAMEs) derived from colza, sunflower, linseed and tung oils and the oxidn. of sunflower FAMEs in the presence of several com. driers based on Co(II), Mn(II), Fe(II), V(IV), Sr(II), Zr(IV), Ca(II), Zn(II) have been investigated. The oxidn. step was studied through oxygen uptake measurements with an automatic O2 pressure recorder (RapidOxy) and by ATR-FTIR spectroscopy. Pure Me linoleate hydroperoxides (ROOH) were prepd. by photooxidn. to follow their decompn. by HPLC in the presence of the driers. Only Co(II), Mn(II) and Fe(II) as primary driers have catalytic effects both on the oxidn. and on the ROOH decompn. steps. However, the Co-based drier shows the higher oxidn. rate while the Fe-based drier has the greater ROOH decompn. rate. On the other hand, oxidn. runs faster by increasing the amt. of driers from 2.5 to 25-50 mM but an antioxidant behavior is obsd. at higher levels. Secondary driers show poor or no catalytic activities both on the oxidn. and the ROOH decompn. steps with a conversion ranging from 5 to 9% over 24 h. Combinations of driers were finally investigated to highlight possible synergistic or antagonist effects during the oxidn. and hydroperoxides decompn. steps. Synergistic effects were found only on the oxidn. stage with Co(II)-Zn(II), Mn(II)-Zn(II) and Fe(II)-Ca(II), while these latter do not have influence on the decompn. step.
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  55. 55
    Tamburini, D.; Sardi, D.; Spepi, A.; Duce, C.; Tinè, M. R.; Colombini, M. P.; Bonaduce, I. An investigation into the curing of urushi and tung oil films by thermoanalytical and mass spectrometric techniques. Polym. Degrad. Stab. 2016, 134, 251– 264,  DOI: 10.1016/j.polymdegradstab.2016.10.015
    Google Scholar
    55
    An investigation into the curing of urushi and tung oil films by thermoanalytical and mass spectrometric techniques
    Tamburini, Diego; Sardi, Dario; Spepi, Alessio; Duce, Celia; Tine, Maria Rosaria; Colombini, Maria Perla; Bonaduce, Ilaria
    Polymer Degradation and Stability (2016), 134 (), 251-264CODEN: PDSTDW; ISSN:0141-3910. (Elsevier Ltd.)
    Urushi is the oldest and most precious lacquer used since antiquity in East Asia. For artistic purposes, to obtain suitable rheol. properties, the lacquer is usually mixed with a vegetable oil. In this work we studied the curing process of urushi/tung oil mixts. to highlight the chem. interactions at the mol. level between the two materials. A multi-anal. approach was adopted, based on thermogravimetry (TG), differential scanning calorimetry (DSC), gas chromatog.-mass spectrometry (GC-MS), evolved gas anal.-mass spectrometry (EGA-MS), anal. pyrolysis coupled with gas chromatog. and mass spectrometry (Py-GC-MS) and high performance liq. chromatog.-mass spectrometry (HPLC-MS). Fresh and aged mixts. were analyzed and the results were compared with those obtained from the anal. of the individual materials. The data highlighted that different polymn. and oxidn. mechanisms take place in oil/urushi mixts. compared to the pure materials. Py-GC-MS and GC-MS showed that the profile of aliph. mono- and di-carboxylic acids was drastically different for the aged film of pure tung oil compared to the mixts. The ratio between the relative content of azelaic and palmitic acids was much lower in the mixts. than in the pure oil, highlighting a lower level of oxidn. The relative content of short chain carboxylic acids, which are produced by pyrolysis of the crosslinked oil network, increased as the concn. of urushi in the mixts. increased, thus indicating an increasing level of reticulation. HPLC-MS showed a relatively higher amt. of triglycerides with hydroxylated fatty acids - the intermediate oxidn. product of polyunsatd. fatty acids - in the mixts. with respect to pure tung oil.
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  56. 56
    Frankel, E. N. Volatile lipid oxidation products. Prog. Lipid Res. 1983, 22, 1– 33,  DOI: 10.1016/0163-7827(83)90002-4
    Google Scholar
    56
    Volatile lipid oxidation products
    Frankel, E. N.
    Progress in Lipid Research (1983), 22 (1), 1-33CODEN: PLIRDW; ISSN:0163-7827.
    A review with 222 refs. on the formation of volatile flavor- and odor-related compds. in food during oxidative lipid deterioration.
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  57. 57
    Hess, P. S.; O’Hare, G. A. Oxidation of linseed oil. Ind. Eng. Chem. 1950, 42, 1424– 1431,  DOI: 10.1021/ie50487a044
    Google Scholar
    57
    Oxidation of linseed oil. Temperature effects
    Hess, P. S.; O'Hare, G. A.
    Industrial and Engineering Chemistry (1950), 42 (), 1424-31CODEN: IECHAD; ISSN:0019-7866.
    The effects exerted by differences in reaction temp. on induction period and on bulk oxypolymerization of raw linseed oil under otherwise const. conditions of air flow and agitation are discussed. At 84-200° the initial viscosity increase rate is identical for all temps. At a definite point in the oxidation a change occurs in the viscosity increase rate, making it possible to show at least 3 distinct temp. regions (above 130°, 84-130°, and below 84°), each characterized by different types of oxidative changes. In the intermediate temp. range the length of the induction period decreases exponentially with unit increase in temp.; the induction period is of very short duration at 130° and above. During the initial stages of oxypolymerization the peroxide value increase is independent of the temp. in the 84-200° range; the max. value, however, is a definite function of temp., higher values corresponding to lower reaction temps. Ultraviolet absorption analyses indicate that the formation of diconjugated systems reaches a max. and that at 84-200° the diene configuration as detd. by the characteristic inflection at 232 mμ is never appreciably greater than 5%; higher values are obtained at lower reaction temps. The results obtained in this study agree with the free radical propagation theory of oil oxidation and appear to indicate the formation of an intermediate prior to oxidative mol. wt. build-up. This intermediate may be of the chelate type and oxidative mol. wt. increases may take place partially by assocn. of intermediates to double mols. by H bonding.
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  58. 58
    Labuza, T. P.; Dugan, L. R., Jr. Kinetics of lipid oxidation in foods. Crit. Rev. Food Sci. Nutr. 1971, 2, 355– 405,  DOI: 10.1080/10408397109527127
    Google Scholar
    There is no corresponding record for this reference.
  59. 59
    Chan, H. S. The mechanism of autoxidation. Autoxidation of Unsaturated Lipids; Academia Press, 1987.
    Google Scholar
    There is no corresponding record for this reference.
  60. 60
    Ghnimi, S.; Budilarto, E.; Kamal-Eldin, A. The new paradigm for lipid oxidation and insights to microencapsulation of Omega-3 fatty acids. Compr. Rev. Food Sci. Food Saf. 2017, 16, 1206– 1218,  DOI: 10.1111/1541-4337.12300
    Google Scholar
    60
    The New Paradigm for Lipid Oxidation and Insights to Microencapsulation of Omega-3 Fatty Acids
    Ghnimi, Sami; Budilarto, Elisabeth; Kamal-Eldin, Afaf
    Comprehensive Reviews in Food Science and Food Safety (2017), 16 (6), 1206-1218CODEN: CRFSBJ; ISSN:1541-4337. (Institute of Food Technologists)
    The consumption of omega-3 fatty acids provides a wide range of health benefits. However, the incorporation of these fatty acids in foods is limited because of their high oxidative instability. A new paradigm has emerged to better explain the oxidn. mechanism of polyunsatd. fatty acids, which will be discussed here with ref. to bulk lipids considered a special case of water in oil microemulsion. This paradigm suggests that lipid oxidn. reactions are initiated by heterogeneous catalysis by metal oxides followed by the formation of micelles contg. initial hydroperoxides, water, and other amphiphilic compds. The induction period comes to the end when the formed micelles reach a crit. micelle concn. and start to decomp. opening the way to intense free radical reactions. Antioxidants and synergists extend the induction period not only by scavenging free radicals but also by stabilizing the micelles. With better understanding of the lipid oxidn. mechanism, a tailored choice of antioxidants and synergistic combinations, and efficient encapsulation methods may be optimized to provide stable encapsulates contg. highly n-3 polyunsatd. fatty acids. Smart processing and encapsulation technologies utilizing properly stabilized oils as well as optimized packaging parameters aiming to enhance n-3 fatty acid stability by smart selection/design of antioxidants, control of the interfacial physics and chem., and elimination of surface oil are needed for this purpose.
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  61. 61
    Thomas, A.; Matthäus, B.; Fiebig, H. J. Fats and fatty oils. Ullmann’s Encyclopedia of Industrial Chemistry; Wiley-VCH, 2000; pp 1– 84.
    Google Scholar
    There is no corresponding record for this reference.
  62. 62
    Xia, W.; Budge, S. M. Techniques for the Analysis of Minor Lipid Oxidation Products Derived from Triacylglycerols: Epoxides, Alcohols, and Ketones. Compr. Rev. Food Sci. Food Saf. 2017, 16, 735– 758,  DOI: 10.1111/1541-4337.12276
    Google Scholar
    62
    Techniques for the Analysis of Minor Lipid Oxidation Products Derived from Triacylglycerols: Epoxides, Alcohols, and Ketones
    Xia, Wei; Budge, Suzanne M.
    Comprehensive Reviews in Food Science and Food Safety (2017), 16 (4), 735-758CODEN: CRFSBJ; ISSN:1541-4337. (Institute of Food Technologists)
    Lipid oxidn. can lead to flavor and safety issues in fat-contg. foods. In order to measure the extent of lipid oxidn., hydroperoxides and their scission products are normally targeted for anal. purposes. In recent years, the formation of rarely monitored oxygenated products, including epoxides, alcs., and ketones, has also raised concerns. These products are thought to form from alternative pathways that compete with chain scissions, and should not be neglected. In this review, a no. of instrumental techniques and approaches to det. epoxides, alcs., and ketones are discussed, with a focus on their selectivity and sensitivity in applications to food lipids and oils. Special attention is given to methods employing gas chromatog. (GC), high-performance liq. chromatog. (HPLC), and NMR (NMR). For characterization purposes, GC-mass spectrometry (GC-MS) provides valuable information regarding the structures of individual oxygenated fatty acids, typically as Me esters, isolated from oxygenated triacylglycerols (TAGs), while the use of liq. chromatog.-MS (LC-MS) techniques allows anal. of intact oxygenated TAGs and offers information about the position of the oxygenated acyl chain on the glycerol backbone. For quant. purposes, traditional chromatog. methods have exhibited excellent sensitivity, while spectroscopic methods, including NMR, are superior to chromatog. for their rapid anal. cycles. Future studies should focus on the development of a routine quant. method that is both selective and sensitive.
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  63. 63
    Duce, C.; Bernazzani, L.; Bramanti, E.; Spepi, A.; Colombini, M. P.; Tiné, M. R. Alkyd artists’ paints: Do pigments affect the stability of the resin? A TG and DSC study on fast-drying oil colours. Polym. Degrad. Stab. 2014, 105, 48– 58,  DOI: 10.1016/j.polymdegradstab.2014.03.035
    Google Scholar
    63
    Alkyd artists' paints: Do pigments affect the stability of the resin? A TG and DSC study on fast-drying oil colours
    Duce, C.; Bernazzani, L.; Bramanti, E.; Spepi, A.; Colombini, M. P.; Tine, M. R.
    Polymer Degradation and Stability (2014), 105 (), 48-58CODEN: PDSTDW; ISSN:0141-3910. (Elsevier Ltd.)
    We studied ten alkyd artists' paints from the Griffin Alkyd, "fast drying oil colors" series (Winsor & Newton) in order to evaluate the effect of pigment-binder interactions on the stability of the alkyd resin. The literature on alkyd paints has focused above all on the characterization of the paints and their ageing processes using various techniques, however, to the best of our knowledge, research on pigment-resin interaction is still lacking. We selected four alkyd colors (red, blue, yellow and green) in two formulations based on inorg. or org. pigments together with titanium white and black formulated with carbonized bones and we applied a combined differential scanning calorimetric (DSC) and thermogravimetric (TG) approach. The pure pigments and the whole paint replicas were analyzed, and the effect of natural ageing on the paints was monitored for eight months. Artificial ageing in an acetic acid atm. was also studied. We found that org. and metallorg. pigments interacted the strongest with the alkyd resin, while the inorg. pigments appear to act more as dispersants. The chem. drying of the paint on the other hand, via auto-oxidn., is almost independent of the pigment and only depends on the alkyd content. The paint is fully dried after eight months. Paint samples from two hyper-realistic artworks, "Salto di qualita´", 2003, and "Senza nome", 2007, by the Italian painter Patrizia Zara were investigated by DSC in order to evaluate the effects of several years of natural ageing on alkyd fast-drying oil colors. At the end of chem. drying, the alkyd colors seemed very stable. Artificial acid ageing visibly damaged the paint replicas, but appeared to act mostly on the pigment rather than on the resin network.
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  64. 64
    Ploeger, R.; Scalarone, D.; Chiantore, O. The characterization of commercial artists’ alkyd paints. J. Cult. Herit. 2008, 9, 412– 419,  DOI: 10.1016/j.culher.2008.01.007
    Google Scholar
    There is no corresponding record for this reference.
  65. 65
    Mallégol, J.; Gonon, L.; Commereuc, S.; Verney, V. Thermal (DSC) and chemical (iodometric titration) methods for peroxides measurements in order to monitor drying extent of alkyd resins. Prog. Org. Coat. 2001, 41, 171– 176,  DOI: 10.1016/s0300-9440(01)00144-8
    Google Scholar
    65
    Thermal (DSC) and chemical (iodometric titration) methods for peroxides measurements in order to monitor drying extent of alkyd resins
    Mallegol, J.; Gonon, L.; Commereuc, S.; Verney, V.
    Progress in Organic Coatings (2001), 41 (1-3), 171-176CODEN: POGCAT; ISSN:0300-9440. (Elsevier Science S.A.)
    Calcn. of the peroxide value of an oxidizing coating appears to be the best way of evaluating the drying extent. For instance, indentation hardness can be measured as an indication of the extent of cure, but it can bring no information about further potential evolution of the network that may occur whether there are still peroxides. Iodometry and DSC have proven to be valuable methods for the detn. of peroxide concn. in oil-based coatings. For a given substrate involved in the oxidn. reaction, such as drying oil in this study, this heat of reaction can be considered as const. but introduction of a drier can increase this energy by lowering decompn. energy of peroxides. We have also obsd. that in systems different from drying oils, the heat of reaction can be very modified when radicals produced by peroxide decompn. react on different unsatd. chains. DSC has shown to be a potential method of differentiating types of peroxide decompn. (monomol. or bimol.). The occurrence of each type of decompn. measured by peak deconvolution may become a very useful tool in the detn. of oxidn. mechanisms in polymeric coatings submitted to thermo- or photo-ageing.
    >> More from SciFinder ®
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  66. 66
    Eglinton, G.; Hunneman, D. H.; McCormick, A. Gas chromatographic-mass spectrometric studies of long chain hydroxy acids.-III.1 The mass spectra of the methyl esters trimethylsilyl ethers of aliphatic hydroxy acids. A facile method of double bond location. Org. Mass Spectrom. 1968, 1, 593– 611,  DOI: 10.1002/oms.1210010413
    Google Scholar
    66
    Gas chromatographic--mass spectrometric studies of long chain hydroxy acids. III. The mass spectra of the methyl esters trimethylsilyl ethers of aliphatic hydroxy acids. A facile method of double bond location
    Eglinton, Geoffrey; Hunneman, D. H.; McCormick, Andrew
    Organic Mass Spectrometry (1968), 1 (4), 593-611CODEN: ORMSBG; ISSN:0030-493X.
    Trimethylsilylation has proved to be extremely useful in the gas chromatog. and the mass spectrometry of hydroxy acid methyl esters. The characteristic mass spectral fragmentation patterns have shown these derivs. to be superior in some respects to others for structural elucidation; in particular, hydroxylation followed by trimethylsilylation provides a useful method of double bond location in unsatd. fatty acid esters.
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  67. 67
    Chiavari, G.; Fabbri, D.; Prati, S. Effect of pigments on the analysis of fatty acids in siccative oils by pyrolysis methylation and silylation. J. Anal. Appl. Pyrolysis 2005, 74, 39– 44,  DOI: 10.1016/j.jaap.2004.11.013
    Google Scholar
    67
    Effect of pigments on the analysis of fatty acids in siccative oils by pyrolysis methylation and silylation
    Chiavari, Giuseppe; Fabbri, Daniele; Prati, Silvia
    Journal of Analytical and Applied Pyrolysis (2005), 74 (1-2), 39-44CODEN: JAAPDD; ISSN:0165-2370. (Elsevier B.V.)
    The relative abundance of the dicarboxylic acids azelaic (nonanedioic) and suberic (octanedioic) with respect to monocarboxylic fatty acids is diagnostic for the identification of siccative oils in painting layers. Fatty acids can be produced from the sample by thermal (pyrolysis) and/or chem. (hydrolysis) degrdn., and then detd. by gas chromatog.-mass spectrometry (GC-MS) in the form of Me or trimethylsilyl (TMS) ester derivs. However, the presence of matrix components in the layer (e.g. pigments) might interfere with the anal. procedure. In this study, the presence of three inorg. pigments (cinnabar (HgS), lead white (2PbCO3·Pb(OH)2) and zinc white (ZnO)) in linseed oil layers was investigated in relation to the detn. of fatty acids by anal. pyrolysis with in situ derivatization. Two methods were applied: pyrolysis/methylation with tetramethylammonium hydroxide (TMAH) and pyrolysis/silylation with hexamethyldisilazane (HMDS), both in combination with online GC-MS. Pyrolysis/methylation and, to a lesser extent, pyrolysis/silylation were influenced by the presence of the pigments which caused a significant decrease in the relative content of azelaic acid. Discriminating siccative oil from egg tempera might be problematic in the presence of lead white and zinc white. Reactive pyrolysis-GC-MS was compared with the classical wet method (alk. hydrolysis, silylation, GC-MS anal.) and the effect of sample prepn. was considered.
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  68. 68
    Rosi, F.; Cartechini, L.; Monico, L.; Gabrieli, F.; Vagnini, M.; Buti, D.; Doherty, B.; Anselmi, C.; Brunetti, B. G.; Miliani, C. Tracking metal oxalates and carboxylates on painting surfaces by non-invasive reflection mid-FTIR spectroscopy. Metal Soaps in Art; Springer, 2019; pp 173– 193.
    Google Scholar
    There is no corresponding record for this reference.
  69. 69
    Bordignon, F.; Postorino, P.; Dore, P.; Tabasso, M. L. The formation of metal oxalates in the painted layers of a medieval polychrome on stone, as revealed by micro-Raman spectroscopy. Stud. Conserv. 2008, 53, 158– 169,  DOI: 10.1179/sic.2008.53.3.158
    Google Scholar
    69
    The formation of metal oxalates in the painted layers of a medieval polychrome on stone, as revealed by micro-Raman spectroscopy
    Bordignon, Francesca; Postorino, Paolo; Dore, Paolo; Tabasso, Marisa Laurenzi
    Studies in Conservation (2008), 53 (3), 158-169CODEN: SCONAH; ISSN:0039-3630. (International Institute for Conservation of Historic and Artistic Works)
    This paper reports a detailed study of the degrdn. phenomena exhibited by the painted bas-relief sculpture on the portal of the Basilica of San Zeno Maggiore in Verona. This study extends the wide diagnostic project started previously by the Istituto Centrale per il Restauro (ICR, Rome). Micro-Raman measurements on polished cross-sections of samples from the painted lunette allowed detailed identification of the species present in the different layers, thanks to the high spatial resoln. and chem. selectivity of this technique. One of the most interesting findings was the occurrence of large amts. of metal oxalates. In particular, in addn. to calcium oxalates, copper oxalate was obsd. in layers contg. copper-based pigments, and data on the distribution of both these oxalates within the painted layers were obtained. The results give evidence of the nature of the degrdn. processes taking place involving the painting materials, provide information about the degree of degrdn., and make it possible to advance reliable hypotheses on the causes and mechanisms of ageing. Along with calcium oxalates, copper oxalate proves to be a reliable marker for degrdn., which is of general interest for the study of outdoor paintings contg. copper-based pigments.
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  70. 70
    van Loon, A.; Gambardella, A. A.; Gonzalez, V.; Cotte, M.; De Nolf, W.; Keune, K.; Leonhardt, E.; de Groot, S.; Gaibor, A. N. P.; Vandivere, A. Out of the blue: Vermeer’s use of ultramarine in Girl with a Pearl Earring. Heritage Sci. 2020, 8, 25,  DOI: 10.1186/s40494-020-00364-5
    Google Scholar
    There is no corresponding record for this reference.

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  • Abstract

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    Figure 1

    Figure 1. Oxygen uptake curves vs time of model oil paints. Curves are recorded under air flow at a constant temperature of 80 °C, and data are normalized for the oil content. (A) LO (solid gray line), LWLO (dashed and dotted light-blue line) and UBLO (dashed blue line); (B) SO (solid black line), LWSO (dashed and dotted red line), and UBSO (dashed pink line).

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    Figure 2

    Figure 2. DSC curves—normalized to the oil content—of model oil paintings recorded up to 24 months of natural aging. (A) LWLO (light blue line); (B) UBLO (blue line); (C) LWSO (red line); (D) UBSO (pink line).

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    Figure 3

    Figure 3. Extracted ion pyrograms of m/z 129 of model oil paintings after 7 (7 m) and 24 months (24 m) of natural aging. In the insets, the chromatographic profiles of unsaturated fatty acids are reported. m/z 339: octadecenoic acid (oleic acid), m/z: 337: octadecadienoic acid (linoleic acid). As reference, the extract ion of octadecanoic acid (stearic acid) is reported (m/z: 341). (A) LWLO; (B) UBLO; (C) LWSO; (D) UBSO.

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    Figure 4

    Figure 4. Summary of the principal results obtained in the study.

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  • References

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    This article references 70 other publications.

    1. 1
      Honzíček, J. Curing of Air-Drying Paints: A Critical Review. Ind. Eng. Chem. Res. 2019, 58, 12485– 12505,  DOI: 10.1021/acs.iecr.9b02567
      Google Scholar
      1
      Curing of Air-Drying Paints: A Critical Review
      Honzicek, Jan
      Industrial & Engineering Chemistry Research (2019), 58 (28), 12485-12505CODEN: IECRED; ISSN:0888-5885. (American Chemical Society)
      A review. This review provides an overview of air-drying binders and chem. processes responsible for their solidification and hardening. It is focused not only on binders derived from plant oils but also on oriental lacquers and their synthetic congeners as their curing is also based on chem. reactions with air-oxygen. The main aim of this review is to bring a crit. view on the mechanism of the autoxidn. process relevant to paint technol. and highlight the previous misinterpretation, remaining open questions, and gaps in the current state of knowledge. Such an objective was achieved by utilization of the latest knowledge appearing in various areas of the chem. research, e.g., org. chem., biochem., phys. chem., computational chem., and inorg. chem. Considerable attention is also given to recent developments in the field of transition metal driers and additives including clarification the role of cobalt-based driers and an updated overview of cobalt replacement.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXht1aqsb3J&md5=3d574a68e8897a37756a5d9b16308be2
    2. 2
      Burnstock, A.; van den Berg, K. J. Twentieth century oil paint. The interface between science and conservation and the challenges for modern oil paint research. Issues in Contemporary Oil Paint; Springer, 2014; pp 1– 19.
      Google Scholar
      There is no corresponding record for this reference.
    3. 3
      Hofland, A. Alkyd resins: From down and out to alive and kicking. Prog. Org. Coat. 2012, 73, 274– 282,  DOI: 10.1016/j.porgcoat.2011.01.014
      Google Scholar
      3
      Alkyd resins: From down and out to alive and kicking
      Hofland, Ad
      Progress in Organic Coatings (2012), 73 (4), 274-282CODEN: POGCAT; ISSN:0300-9440. (Elsevier B.V.)
      A review. Alkyd resins have been introduced in the 1930s as binders for paints. They are suitable for the prodn. of a very broad range of coating materials. When properly formulated, alkyd emulsions can be considered as candidates to formulate paints with a zero VOC level. This paper summarizes the new developments in alkyd emulsions and high solid alkyd paints and compares these paint systems with paints based on acrylic dispersions as other environmentally friendly alternatives to conventional paints.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XjtVOrtrk%253D&md5=a1e308af020ad3eaecebd1d9f160ce92
    4. 4
      Lindeboom, J. Air-drying high solids alkyd pants for decorative coatings. Prog. Org. Coat. 1998, 34, 147– 151,  DOI: 10.1016/s0300-9440(98)00034-4
      Google Scholar
      4
      Air-drying high solids alkyd paints for decorative coatings
      Lindeboom, Jan
      Progress in Organic Coatings (1998), 34 (1-4), 147-151CODEN: POGCAT; ISSN:0300-9440. (Elsevier Science S.A.)
      A review with 3 refs.; the restrictions on the emission of solvents in paints makes the need for environmentally-friendly systems still more important. For industrial applications, powder coatings and water-borne systems are the most attractive alternatives and are already in use. For architectural purposes, there is a min. acceptance of water-borne systems (except wall paints). In this application, high solids are becoming more and more accepted as an alternative to traditional systems, not only because of their environmental effects but also for their tech. performance and economical benefits.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXkvFKjtrg%253D&md5=7be9c7c844f6fe71ca2d4e4186a30a96
    5. 5
      Athawale, V. D.; Nimbalkar, R. V. Waterborne coatings based on renewable oil resources: an overview. J. Am. Oil Chem. Soc. 2011, 88, 159– 185,  DOI: 10.1007/s11746-010-1668-9
      Google Scholar
      5
      Waterborne Coatings Based on Renewable Oil Resources: an Overview
      Athawale, Vilas D.; Nimbalkar, Ramakant V.
      Journal of the American Oil Chemists' Society (2011), 88 (2), 159-185CODEN: JAOCA7; ISSN:0003-021X. (Springer)
      A review. Polyurethane dispersions are gaining in importance due to their environmentally friendly coating system, versatile coating properties and ease of application. An enormous amt. of research is focused on waterborne coatings such as waterborne alkyds, water-reducible alkyds, alkyd-acrylic hybrids, oil modified polyurethane dispersions and their composite latexes. This review gives a comprehensive compilation of recent studies on the synthesis and applications of waterborne coatings. The article specifically covers all of the research work carried out in the field of waterborne alkyd-acrylics, polyurethane dispersions and their hybrid latexes systematically.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhvVajsbw%253D&md5=e2afb380e10a8b4fddcb202b08925aea
    6. 6
      Frankel, E. N. Lipid Oxidation; Woodhead Publishing Limited: Cambridge, 2012.
      Google Scholar
      There is no corresponding record for this reference.
    7. 7
      Shahidi, F. Bailey’s Industrial Oil and Fat Products, Edible Oil and Fat Products: Processing Technologies; John Wiley & Sons, 2005; Vol. 5.
      Google Scholar
      There is no corresponding record for this reference.
    8. 8
      Lazzari, M.; Chiantore, O. Drying and oxidative degradation of linseed oil. Polym. Degrad. Stab. 1999, 65, 303– 313,  DOI: 10.1016/s0141-3910(99)00020-8
      Google Scholar
      8
      Drying and oxidative degradation of linseed oil
      Lazzari, Massimo; Chiantore, Oscar
      Polymer Degradation and Stability (1999), 65 (2), 303-313CODEN: PDSTDW; ISSN:0141-3910. (Elsevier Science Ltd.)
      The drying and oxidative degrdn. of linseed oil have been investigated through exposition of samples in form of thin films to indoor lab. conditions, or treated at a const. temp. of 80°C, or with irradn. at wavelengths > 295 mm. Structure and property changes resulted almost independent of the different treatments and were followed by FTIR spectra, TGA, DSC, insols. detn.- and size-exclusion chromatog. The initial phase of drying consists of the autoxidn. phenomenon of the unsatd. fatty acid components with the development of extensive crosslinking, together with formation of conjugated unsatns. The following stage of slow consumption of labile crosslinks gives rise to a highly stable network, which contains small amts. of low mol. wt. mols., either formed by fragmentation or still present as unreacted triglycerides. The oxidative degrdn. of linseed oil consists of the continuation of the hardening process, and only after long periods of artificial ageing, corresponding to years of natural ageing, the oxidn. also takes place on the alkyl segments, leading to partial fragmentation of the structure.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXksFekt78%253D&md5=847e4ff23473f2eb4ea3e1b4527156c1
    9. 9
      Boon, J. J.; Peulvé, S.; van den Brink, O. F.; Duursma, M. C.; Rainford, D. In Molecular Aspects of Mobile and Stationary Phases in Aging Tempera and Oil Paint Films. Early Italian Paintings Techniques and Analysis, Symposium, Maastricht; Bakkenist, T., Hoppenbrouwers, R., Dubois, H., Eds.; Limburg Conservation Institute: Maastricht, 1996; pp 35– 56.
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      There is no corresponding record for this reference.
    10. 10
      Bonaduce, I.; Duce, C.; Lluveras-Tenorio, A.; Lee, J.; Ormsby, B.; Burnstock, A.; van den Berg, K. J. Conservation Issues of Modern Oil Paintings: A Molecular Model on Paint Curing. Acc. Chem. Res. 2019, 52, 3397– 3406,  DOI: 10.1021/acs.accounts.9b00296
      Google Scholar
      10
      Conservation Issues of Modern Oil Paintings: A Molecular Model on Paint Curing
      Bonaduce, Ilaria; Duce, Celia; Lluveras-Tenorio, Anna; Lee, Judith; Ormsby, Bronwyn; Burnstock, Aviva; van den Berg, Klaas Jan
      Accounts of Chemical Research (2019), 52 (12), 3397-3406CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)
      Conspectus: The 20th and 21st century oil paintings are presenting a range of challenging conservation problems that can be distinctly different from those noted in paintings from previous centuries. These include the formation of vulnerable surface "skins" of medium and exudates on paint surfaces, efflorescence, unpredictable water and solvent sensitivity, and incidence of paint dripping which can occur within a few years after the paintings were completed. Physicochem. studies of modern oil paints and paintings in recent years have identified a range of possible causal factors for the noted sensitivity of painting surfaces to water and protic solvents, including the formation of water-sol. inorg. salts and/or the accumulation of diacids at the paint surface, which are oxidn. products of the oil binder. Other studies have investigated the relationship between water sensitivity and the degree of hydrolysis of the binder, the proportions of free fatty and dicarboxylic acids formed, as well as the relative content of free metal soaps. Thus far, data indicate that the qual. and quant. compn. of the nonpolymd. fractions of the oil binder cannot be solely or directly related to the solvent sensitivity of the paint film. Conclusions therefore indicate that the polymeric network, formed upon the curing of the oil, plays a fundamental role, suggesting that water sensitivity, at least in some cases, may be related to the poor development and/or polar nature of the formed polymeric network rather than the compn. of the nonpolymd. fractions. Poorly developed polymeric networks, in combination with the migration of polar fractions, i.e., dicarboxylic and hydroxylated fatty acids toward the paint surface, can be related to other degrdn. phenomena, including the sepn. and migration of the paint binder which can lead to the presence of observable skins of medium as well as the more alarming phenomenon of liquefying or dripping oil paints. It is thus crucial to understand the mol. compn. of these paints and their physicochem. behavior to aid the further development of appropriate conservation and preservation strategies, as the risks currently assocd. with surface cleaning treatments and other conservation procedures can be unacceptably high. This Account reviews the relationships between the degrdn. phenomena assocd. with modern oil paintings and the chem. compn. of the oil binder and proposes a mol. model for the development of water sensitivity and other noted degrdn. phenomena. It is suggested that water sensitivity (and possibly other degrdn. phenomena) is a consequence of processes that take place upon curing, and in particular to the rate of formation and decompn. of alkoxyl and peroxyl radicals. These reactions are strongly dependent on the type of oil present, the ambient environmental conditions, and the chem. and phys. nature of the pigments and additives present in the paint formulation. When the curing environment is oxidizing, the chem. of peroxyl radicals dominates the reaction pathways, and oxidative decompn. of the paint film overwhelms crosslinking reactions.
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    11. 11
      Bayliss, S.; van den Berg, K. J.; Burnstock, A.; de Groot, S.; van Keulen, H.; Sawicka, A. An investigation into the separation and migration of oil in paintings by Erik Oldenhof. Microchem. J. 2016, 124, 974– 982,  DOI: 10.1016/j.microc.2015.07.015
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      11
      An investigation into the separation and migration of oil in paintings by Erik Oldenhof
      Bayliss, Sarah; van den Berg, Klaas Jan; Burnstock, Aviva; de Groot, Suzan; van Keulen, Henk; Sawicka, Alysia
      Microchemical Journal (2016), 124 (), 974-982CODEN: MICJAN; ISSN:0026-265X. (Elsevier B.V.)
      The observation of disfiguring yellow oil-like material on the surface of paintings by the contemporary Dutch artist Erik Oldenhof led to an investigation of the material and environmental factors causing the migration and surface deposition of the exudate. A combination of material anal., the examn. of artificially aged reconstructions and information provided by the artist and paint manufacturer, Royal Talens, provided evidence that the phenomenon is related to the drying properties of the safflower oil used, the artist's use of thick paint layers and the availability of light while the paint is drying. Reconstructions demonstrated that the exudation phenomenon can be reproduced and is not restricted to one particular range of oil paint or manufacturer. Visual characteristics of the exudate, including its appearance in UV light and SEM back-scattered images, were documented, and the org. and inorg. components of the paint were characterised by SEM-EDX, XRF, THM-PyGC-MS and FTIR. Results confirmed that the exudate is composed of safflower oil derived from the paint binding medium, and that a difference in P/S ratio between the exudate and paint bulk is due to the presence of metal stearates in the paint that have not migrated to the surface.
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    12. 12
      Schaich, K. M. Lipid Oxidation: Theoretical Aspects. In Bailey’s Industrial Oil and Fat Products, 6 ed.; Shahidi, F., Ed.; Wiley, 2005; Vol. 1.
      Google Scholar
      There is no corresponding record for this reference.
    13. 13
      Schaich, K. M. Challenges in Elucidating Lipid Oxidation Mechanisms: When, Where, and How Do Products Arise? In Lipid Oxidation; Logan, A., Nienaber, U., Pan, X., Eds.; AOCS Press, 2013; pp 1– 52.
      Google Scholar
      There is no corresponding record for this reference.
    14. 14
      Schaich, K. M. Lipid Oxidation: New Perspectives on an Old Reaction. In Bailey’s Industrial Oil and Fat Products, 7a ed.; Shahidi, F., Ed.; Wiley, 2020; Vol. 1, pp 1– 72.
      Google Scholar
      There is no corresponding record for this reference.
    15. 15
      Choe, E.; Min, D. B. Chemistry and Reactions of Reactive Oxygen Species in Foods. Crit. Rev. Food Sci. Nutr. 2006, 46, 1– 22,  DOI: 10.1080/10408390500455474
      Google Scholar
      15
      Chemistry and reactions of reactive oxygen species in foods
      Choe, Eunok; Min, David B.
      Critical Reviews in Food Science and Nutrition (2006), 46 (1), 1-22CODEN: CRFND6; ISSN:1040-8398. (Taylor & Francis, Inc.)
      A review. Reactive oxygen species (ROS) are formed enzymically, chem., photochem., and by irradn. of food. They are also formed by the decompn. and the inter-reactions of ROS. Hydroxy radical is the most reactive ROS, followed by singlet oxygen. Reactions of ROS with food components produce undesirable volatile compds. and carcinogens, destroy essential nutrients, and change the functionalities of proteins, lipids, and carbohydrates. Lipid oxidn. by ROS produces low mol. volatile aldehydes, alcs., and hydrocarbons. ROS causes crosslink or cleavage of proteins and produces low mol. carbonyls from carbohydrates. Vitamins are easily oxidized by ROS, esp. singlet oxygen. The singlet oxygen reaction rate was the highest in ss-carotene, followed by tocopherol, riboflavin, vitamin D, and ascorbic acid.
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    16. 16
      Chang, C.; Wu, G.; Zhang, H.; Jin, Q.; Wang, X. Deep-fried flavor: characteristics, formation mechanisms, and influencing factors. Crit. Rev. Food Sci. Nutr. 2020, 60, 1496– 1514,  DOI: 10.1080/10408398.2019.1575792
      Google Scholar
      16
      Deep-fried flavor: characteristics, formation mechanisms, and influencing factors
      Chang, Chang; Wu, Gangcheng; Zhang, Hui; Jin, Qingzhe; Wang, Xingguo
      Critical Reviews in Food Science and Nutrition (2020), 60 (9), 1496-1514CODEN: CRFND6; ISSN:1040-8398. (Taylor & Francis, Inc.)
      A review. Deep-fried flavor, involving fatty, sweet, burnt, and grilled odors, is an important factor leading to the popularity of deep-fried foods. Comparing with flavors from other conventional and innovative thermal treatments, deep-fried flavor is characterized by a rich variety of volatile species (e.g. aldehydes, alcs., ketones, hydrocarbons, carboxylic acids, furans, pyrazines, and pyridines), intricate formation mechanisms, and a stronger attraction to consumers. By means of comprehensively literature research, this article critically reviews deep-fried flavor deriving from lipid oxidn., Maillard reaction, hydrolysis and amino acid degrdn., with a special emphasis to discuss the involvement of lipid oxidn. products in the Maillard pathway to form fried volatiles via secondary processes (e.g. fragmentation, rearrangement, and degrdn.). The reactions are interacted and influenced by various factors, such as frying oils (e.g. fatty acid compn. and oil type), food components (e.g. amino acid and sugar), frying conditions (e.g. oxygen concn., frying time, temp., pH, and moisture content), and frying types (e.g. vacuum frying and air frying). Overall, well understanding of chem. origins of deep-fried volatiles is meaningful to economically manipulate the frying process, optimize the fried flavor, and improve the safety and consumer acceptance of deep-fried foods.
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    17. 17
      Guéraud, F.; Atalay, M.; Bresgen, N.; Cipak, A.; Eckl, P. M.; Huc, L.; Jouanin, I.; Siems, W.; Uchida, K. Chemistry and biochemistry of lipid peroxidation products. Free Radical Res. 2010, 44, 1098– 1124,  DOI: 10.3109/10715762.2010.498477
      Google Scholar
      17
      Chemistry and biochemistry of lipid peroxidation products
      Gueraud, F.; Atalay, M.; Bresgen, N.; Cipak, A.; Eckl, P. M.; Huc, L.; Jouanin, I.; Siems, W.; Uchida, K.
      Free Radical Research (2010), 44 (10), 1098-1124CODEN: FRARER; ISSN:1071-5762. (Informa Healthcare)
      A review. Oxidative stress and resulting lipid peroxidn. is involved in various and numerous pathol. states including inflammation, atherosclerosis, neurodegenerative diseases and cancer. This review is focused on recent advances concerning the formation, metab. and reactivity towards macromols. of lipid peroxidn. breakdown products, some of which being considered as second messengers' of oxidative stress. This review relates also new advances regarding apoptosis induction, survival/proliferation processes and autophagy regulated by 4-hydroxynonenal, a major product of omega-6 fatty acid peroxidn., in relationship with detoxication mechanisms. The use of these lipid peroxidn. products as oxidative stress/lipid peroxidn. biomarkers is also addressed.
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    18. 18
      Cheeseman, K. H.; Slater, T. F. An introduction to free radical biochemistry. Br. Med. Bull. 1993, 49, 481– 493,  DOI: 10.1093/oxfordjournals.bmb.a072625
      Google Scholar
      18
      An introduction to free radical biochemistry
      Cheeseman, K. H.; Slater, T. F.
      British Medical Bulletin (1993), 49 (3), 481-93CODEN: BMBUAQ; ISSN:0007-1420.
      A review with 42 refs. Oxygen free radicals and reactive oxygen species, prodn. of free radicals in cells, damaging reactions of free radicals, defences against free radicals, and free radicals in human disease were discussed.
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    19. 19
      Hage, R.; de Boer, J. W.; Maaijen, K. Manganese and Iron Catalysts in Alkyd Paints and Coatings. Inorganics 2016, 4, 11,  DOI: 10.3390/inorganics4020011
      Google Scholar
      19
      Manganese and iron catalysts in alkyd paints and coatings
      Hage, Ronald; De Boer, Johannes W.; Maaijen, Karin
      Inorganics (2016), 4 (2), 11/1-11/18CODEN: INORCW; ISSN:2304-6740. (MDPI AG)
      A review. Many paint, ink and coating formulations contain alkyd-based resins which cure via autoxidn. mechanisms. While cobalt-soaps have been used for many decades, there is a continuing and accelerating desire by paint companies to develop alternatives for the cobalt soaps, due to likely classification as carcinogens under the REACH (Registration, Evaluation, Authorisation and Restriction of Chems.) legislation. Alternative driers, for example manganese and iron soaps, have been applied for this purpose. However, relatively poor curing capabilities make it necessary to increase the level of metal salts to such a level that often coloring of the paint formulation occurs. More recent developments include the application of manganese and iron complexes with a variety of org. ligands. This review will discuss the chem. of alkyd resin curing, the applications and reactions of cobalt-soaps as curing agents, and, subsequently, the paint drying aspects and mechanisms of (model) alkyd curing using manganese and iron catalysts.
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    20. 20
      Vangorkum, R.; Bouwman, E. The oxidative drying of alkyd paint catalysed by metal complexes. Coord. Chem. Rev. 2005, 249, 1709– 1728,  DOI: 10.1016/j.ccr.2005.02.002
      Google Scholar
      There is no corresponding record for this reference.
    21. 21
      Soucek, M. D.; Khattab, T.; Wu, J. Review of autoxidation and driers. Prog. Org. Coat. 2012, 73, 435– 454,  DOI: 10.1016/j.porgcoat.2011.08.021
      Google Scholar
      21
      Review of autoxidation and driers
      Soucek, M. D.; Khattab, T.; Wu, J.
      Progress in Organic Coatings (2012), 73 (4), 435-454CODEN: POGCAT; ISSN:0300-9440. (Elsevier B.V.)
      A review. This article is an overview of the chem. and driers used in autoxidatively cured coatings and in particular alkyds. The drying process for alkyds and other unsatd. fatty acid materials is based on a series of chem. reactions known as autoxidn. The autoxidative process is usually catalyzed by metal salts known as driers. Numerous of investigations have elucidated the catalytic activity and reaction mechanism of the drying process. Spectroscopic techniques, esp. mass spectrometry, have been used to study the autoxidn. process and its products. Recent investigations on the oxidative drying of alkyd coating films are presented with a focus on both metal based and more environmental friendly means of catalysis.
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    22. 22
      Baij, L.; Chassouant, L.; Hermans, J. J.; Keune, K.; Iedema, P. D. The concentration and origins of carboxylic acid groups in oil paint. RSC Adv. 2019, 9, 35559– 35564,  DOI: 10.1039/c9ra06776k
      Google Scholar
      22
      The concentration and origins of carboxylic acid groups in oil paint
      Baij, Lambert; Chassouant, Louise; Hermans, Joen J.; Keune, Katrien; Iedema, Piet D.
      RSC Advances (2019), 9 (61), 35559-35564CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)
      Although the concn. of carboxylic acid (COOH) groups is crucial to understand oil paint chem., anal. challenges hindered COOH quantification in complex polymerised oil samples thus far. The concn. of COOH groups is important in understanding oil paint degrdn. because it drives the breakdown of reactive inorg. pigments to dissolve in the oil network and form metal carboxylates. The metal ions in such an ionomeric polymer network can exchange with satd. fatty acids to form cryst. metal soaps (metal complexes of satd. fatty acids), leading to serious problems in many paintings worldwide. We developed two methods based on ATR-FTIR spectroscopy to accurately est. the COOH concn. in artificially aged oil paint models. Using tailored model systems composed of linseed oil, ZnO and inert filler pigments, these dried oil paints were found to contain one COOH group per triacylglycerol unit. Model systems based on a mixt. of long chain alcs. showed that the calcd. COOH concn. originates from side chain autoxidn. at low relative humidity (RH). The influence of increasing RH and ZnO concn. on COOH formation was studied and high relative humidity conditions were shown to promote the formation of COOH groups. No significant ester hydrolysis was found under the conditions studied. Our results show the potential of quant. anal. of oil paint model systems for aiding careful (re)evaluation of conservation strategies.
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    23. 23
      Bronken, I. A. T.; Boon, J. J. Hard dry paint, softening tacky paint, and exuding drips on composition (1952) by Jean-Paul Riopelle. Issues in Contemporary Oil Paint; Springer, 2014; pp 247– 262.
      Google Scholar
      There is no corresponding record for this reference.
    24. 24
      Erhardt, D.; Tumosa, C. S.; Mecklenburg, M. F. Long-term chemical and physical processes in oil paint films. Stud. Conserv. 2005, 50, 143– 150,  DOI: 10.1179/sic.2005.50.2.143
      Google Scholar
      There is no corresponding record for this reference.
    25. 25
      La Nasa, J.; Lee, J.; Degano, I.; Burnstock, A.; van den Berg, K. J.; Ormsby, B.; Bonaduce, I. The role of the polymeric network in the water sensitivity of modern oil paints. Sci. Rep. 2019, 9, 3467,  DOI: 10.1038/s41598-019-39963-z
      Google Scholar
      25
      The role of the polymeric network in the water sensitivity of modern oil paints
      La Nasa Jacopo; Degano Ilaria; Bonaduce Ilaria; Lee Judith; Ormsby Bronwyn; Burnstock Aviva; van den Berg Klaas Jan
      Scientific reports (2019), 9 (1), 3467 ISSN:.
      Spectroscopic and mass spectrometric analytical techniques were used to characterise two naturally aged Winsor & Newton (W&N) Winsor Green (phthalocyanine green, PG7) artists' oil colour paint swatches dating to 1993 and 2003. Infrared and Energy Dispersive X-ray (EDX) analysis indicated that the swatches were of closely similar composition, yet the swatch from 2003 was water-sensitive whilst the swatch from 1993 was not. Water-sensitivity is a conservation challenge associated with significant numbers of modern oil paintings and this study aimed to further develop our understanding of the molecular causes of water sensitivity. SEM elemental mapping of samples taken from both swatches provided no indication for the formation of epsomite - a known cause of water sensitivity in some modern oil paintings. Liquid chromatography coupled with mass spectrometry (HPLC-MS) and gas chromatography coupled with mass spectrometry (GC-MS) also revealed very similar qualitative-quantitative composition in terms of unbound and esterified medium fractions. The polymeric network was investigated using analytical pyrolysis. A combination of flash pyrolysis coupled with gas chromatography mass spectrometry (Py-GC-MS) together with evolved gas analysis mass spectrometry (EGA-MS) revealed that the polymeric material was relatively more abundant in the non-water-sensitive paint. This is the first multi-analytical study that has demonstrated a correlation between water-sensitivity and the degree of polymerisation of the oil medium; independent of other known causes of water-sensitivity.
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    26. 26
      Modugno, F.; Di Gianvincenzo, F.; Degano, I.; van der Werf, I. D.; Bonaduce, I.; van den Berg, K. J. On the influence of relative humidity on the oxidation and hydrolysis of fresh and aged oil paints. Sci. Rep. 2019, 9, 5533,  DOI: 10.1038/s41598-019-41893-9
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      26
      On the influence of relative humidity on the oxidation and hydrolysis of fresh and aged oil paints
      Modugno Francesca; Di Gianvincenzo Fabiana; Degano Ilaria; Bonaduce Ilaria; Di Gianvincenzo Fabiana; van der Werf Inez Dorothe; van den Berg Klaas Jan
      Scientific reports (2019), 9 (1), 5533 ISSN:.
      Modern oil paintings are affected by conservation issues related to the oil paint formulations and to the fact that they are often unvarnished, and in direct contact with the environment. Understanding the evolution of the molecular composition of modern oil paint during ageing, under the influence of environmental factors, is fundamental for a better knowledge of degradation phenomena and risk factors affecting modern art. We investigated for the first time the influence of relative humidity on the chemical composition of modern oil paints during curing and artificial ageing. For this purpose, modern oil paint layers naturally aged for 10 years were further artificially aged in low and high relative humidity conditions. Moreover, the influence of RH% on the curing of fresh paint layers was studied. The paints used in the experiments are from three suppliers (Old Holland, Winsor&Newton, and Talens), and contain cadmium or cadmium zinc sulfide as main pigment. The changes in the composition of extracts of paint samples were investigated by direct electrospray mass spectrometry with a quadrupole-time of flight mass analyser (ESI-Q-ToF). The obtained mass spectral data were interpreted by means of principal component analysis (PCA) operated on a data set containing the relative abundance of ions associated to significant molecules present in the extracts, and also by calculating the ratios between the signals relative to fatty acids, dicarboxylic acids and acylglycerols, related to hydrolysis and oxidation phenomena. The same paint samples were also analysed, in bulk, by pyrolysis gas chromatography mass spectrometry (Py-GC/MS), achieving chemical information on the total lipid fraction. High performance liquid chromatography (HPLC) ESI-Q-ToF was carried out for the characterisation of the profile of free fatty acids (FFA) and acylglycerols, defining the nature of the oils used in the paint formulations, and for the determination of the degree of hydrolysis. This study demonstrated that relative humidity conditions significantly influence the chemical composition of the paints. Ageing under high RH% conditions produced an increase of the formation of dicarboxylic acids compared to ageing under low RH%, for all paints, in addition to a higher degree of hydrolysis, followed by evaporation of free fatty acids.
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    27. 27
      Tumosa, C. S.; Mecklenburg, M. F. Weight Changes on Oxidation of Drying and Semi-drying Oils, Collection Forum , 2003.
      Google Scholar
      There is no corresponding record for this reference.
    28. 28
      Tumosa, C. S.; Mecklenburg, M. F. The influence of lead ions on the drying of oils. Stud. Conserv. 2005, 50, 39– 47,  DOI: 10.1179/sic.2005.50.supplement-1.39
      Google Scholar
      There is no corresponding record for this reference.
    29. 29
      Van den Berg, K. J.; Bonaduce, I.; Burnstock, A.; Ormsby, B.; Scharff, M.; Carlyle, L.; Heydenreich, G.; Keune, K. Conservation of Modern Oil Paintings; Springer, 2019.
      Google Scholar
      There is no corresponding record for this reference.
    30. 30
      Van den Berg, K. J.; Burnstock, A.; De Keijzer, M.; Krueger, J.; Learner, T.; De Tagle, A.; Heydenreich, G. Issues in Contemporary Oil Paint; Springer, 2014.
      Google Scholar
      There is no corresponding record for this reference.
    31. 31
      Boon, J. J.; Hoogland, F. G. Investigating fluidizing dripping pink commercial paint on Van Hemert’s Seven-series works from 1990–1995. Issues in Contemporary Oil Paint; Springer, 2014; pp 227– 246.
      Google Scholar
      There is no corresponding record for this reference.
    32. 32
      Lee, J.; Bonaduce, I.; Modugno, F.; La Nasa, J.; Ormsby, B.; van den Berg, K. J. Scientific investigation into the water sensitivity of twentieth century oil paints. Microchem. J. 2018, 138, 282– 295,  DOI: 10.1016/j.microc.2018.01.017
      Google Scholar
      32
      Scientific investigation into the water sensitivity of twentieth century oil paints
      Lee, Judith; Bonaduce, Ilaria; Modugno, Francesca; La Nasa, Jacopo; Ormsby, Bronwyn; van den Berg, Klaas Jan
      Microchemical Journal (2018), 138 (), 282-295CODEN: MICJAN; ISSN:0026-265X. (Elsevier B.V.)
      In order to develop a better understanding at the mol. level of water sensitivity in twentieth century oil paintings, water sensitive Winsor & Newton oil paint swatches and twentieth century oil paintings were characterised using gas chromatog.-mass spectrometry (GC-MS) and direct injection electrospray ionisation mass spectrometry (ESI-MS), and the data were analyzed using principal component anal. Liq. chromatog. coupled with tandem mass spectrometry based on quadrupole and time of flight mass detectors and electrospray interface (HPLC-ESI-Q-ToF) was also used to obtain a better insight into the mol. compn. of a selection of samples. The study highlights a strong relationship between the mol. compn. of the binding medium and the type of pigment present in the paint, which relates to water sensitivity. Consistently non-water sensitive lead white, titanium white, and zinc white paints [all contg. zinc oxide] contained a relatively low proportion of extractable diacids, and a relatively high proportion of extractable short chain monoacids. These paints also contained a relatively low level of unsatd. and hydroxylated glycerides. Water sensitive iron oxide and ultramarine paints are assocd. with both a relatively high degree of oxidn. and a high proportion of extractable diacids, as well as a relatively high content of unsatd. and hydroxylated glycerides. Water sensitive cadmium red, yellow and orange paints were generally not highly oxidised, but they also contained a relatively high content of unsatd. and hydroxylated glycerides. It is hypothesised that water sensitivity relates to a low degree of sapon. and crosslinking and possibly, on the relative content of dicarboxylic acids.
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    33. 33
      Fuster-López, L.; Izzo, F. C.; Piovesan, M.; Yusá-Marco, D. J.; Sperni, L.; Zendri, E. Study of the chemical composition and the mechanical behaviour of 20th century commercial artists’ oil paints containing manganese-based pigments. Microchem. J. 2016, 124, 962– 973,  DOI: 10.1016/j.microc.2015.08.023
      Google Scholar
      33
      Study of the chemical composition and the mechanical behaviour of 20th century commercial artists' oil paints containing manganese-based pigments
      Fuster-Lopez, Laura; Izzo, Francesca Caterina; Piovesan, Marco; Yusa-Marco, Dolores J.; Sperni, Laura; Zendri, Elisabetta
      Microchemical Journal (2016), 124 (), 962-973CODEN: MICJAN; ISSN:0026-265X. (Elsevier B.V.)
      The present study deals with 20th century manufd. artists' oil paints contg. raw and burnt umber pigments, this is, natural earth pigments resulting from the combination of iron and manganese oxides. Manganese, in particular, is known to be a primary drier and to have a siccative effect on oil paint films. This research aims to show the diversity of formulations behind apparently same com. names, as well as to understand how the content of manganese, the presence of modern lipidic media and the hydrolysis mechanisms can promote significant differences in the expected mech. properties of oil paint films, thus conditioning their long-term performance. Several manufd. artists' oil paint films contg. manganese were selected. Dried films from raw and burnt umber oil paints by Winsor&Newton (UK), Grumbacher (USA), Gamblin (USA) and Speedball (USA) were studied and information about their chem. compn. and mech. behavior is here presented. In addn. to the identification and the study of the inorg. and org. components present in each formulation through LM, SEM-EDX, FTIR-ATR, XRD, GC-MS anal., tensile tests were run and stress-strain curves were obtained. Together with evident hue differences, the obtained results showed significant differences in the chem. compn. and the mech. behavior of the oil paint films.
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    34. 34
      Artesani, A. Zinc oxide instability in drying oil paint. Mater. Chem. Phys. 2020, 255, 123640,  DOI: 10.1016/j.matchemphys.2020.123640
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      34
      Zinc oxide instability in drying oil paint
      Artesani, Alessia
      Materials Chemistry and Physics (2020), 255 (), 123640CODEN: MCHPDR; ISSN:0254-0584. (Elsevier B.V.)
      In this work, we review recent studies on zinc sapon. mechanisms, which occur as degrdn. products in modern oil paintings and severely affect the cohesion of pictorial layers. The issue has gained great attention in the last decades, when research moved from the mere phenomenon observation to the understating of the crit. behavior of zinc oxide in an oleic matrix. The structure formed by the two paint constituents, i.e. drying oil (polymeric matrix) and pigment (suspended solid particles), demonstrated to represent a fundamental aspect for the instability of the paint film and its ageing showed important analogies with degrdn. of com. ionomer networks. The complexity of the system and the cultural value of the investigated objects has posed great challenges and has required the collaboration between physicists, chemists and conservation scientists to answer both applied and fundamental questions related to this conservative issue. As the research has now reached maturity, this review conveys the acquired knowledge on this topic, summarizing and illustrating the main phases of evolution of the zinc oxide-binder system, corresponding to pigment dispersion and dissoln., formation of the ionomer network and crystn. of metal soaps. The final scope of this work is to guide and pave the way for future studies related to this issue and facing similar problematics.
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    35. 35
      Burnstock, A.; van den Berg, K. J.; de Groot, S.; Wijnberg, L. An investigation of water-sensitive oil paints in twentieth-century paintings. Modern Paints Uncovered, London; Getty Conservation Institute London, 2006; pp 177– 188.
      Google Scholar
      There is no corresponding record for this reference.
    36. 36
      de la Rie, E. R.; Michelin, A.; Ngako, M.; Del Federico, E.; Del Grosso, C. Photo-catalytic degradation of binding media of ultramarine blue containing paint layers: A new perspective on the phenomenon of ″ultramarine disease″ in paintings. Polym. Degrad. Stab. 2017, 144, 43– 52,  DOI: 10.1016/j.polymdegradstab.2017.08.002
      Google Scholar
      36
      Photo-catalytic degradation of binding media of ultramarine blue containing paint layers: A new perspective on the phenomenon of "ultramarine disease" in paintings
      de la Rie, E. Rene; Michelin, Anne; Ngako, Manuela; Del Federico, Eleonora; Del Grosso, Chelsey
      Polymer Degradation and Stability (2017), 144 (), 43-52CODEN: PDSTDW; ISSN:0141-3910. (Elsevier Ltd.)
      Failure of ultramarine blue paint layers in historic as well as modern paintings has been reported in the literature many times and is often referred to as "ultramarine disease" or "ultramarine sickness.". The pigment itself is known to degrade hydrolytically when exposed to acids, but whether this is the primary cause of the failure remains unclear. This paper describes a study in which ultramarine blue paints using linseed oil and a urea-aldehyde resin as binding media were aged under simulated indoor conditions. The paints were analyzed using reflectance spectroscopy, SEM, and Raman and NMR spectroscopy. The urea-aldehyde resin binding medium was analyzed using size exclusion chromatog. and Fourier-transform IR spectroscopy. The study provides evidence of photo-catalytic degrdn. of binding media of ultramarine blue paint layers via free-radical processes, causing changes in reflectance while the pigment itself remains intact. It is believed that this is the primary process behind the degrdn. of ultramarine blue paint layers in paintings.
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    37. 37
      Hermans, J. J.; Keune, K.; van Loon, A.; Corkery, R. W.; Iedema, P. D. Ionomer-like structure in mature oil paint binding media. RSC Adv. 2016, 6, 93363– 93369,  DOI: 10.1039/c6ra18267d
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      37
      Ionomer-like structure in mature oil paint binding media
      Hermans, Joen J.; Keune, Katrien; van Loon, Annelies; Corkery, Robert W.; Iedema, Piet D.
      RSC Advances (2016), 6 (96), 93363-93369CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)
      IR spectra of samples from oil paintings often show metal carboxylate bands that are broader and shifted compared to those of cryst. metal soap stds. (metal complexes of long-chain satd. fatty acids). Using quant. attenuated total reflection Fourier transform IR spectroscopy (ATR-FTIR), it is demonstrated that the broad metal carboxylate band is typically too intense to be explained by carboxylates adsorbed on the surface of pigment particles or disordered metal complexes of satd. fatty acids. The metal carboxylate species assocd. with the broad bands must therefore be an integral part of the polymd. binding medium. Small-angle X-ray scattering (SAXS) measurements on model ionomer systems based on linseed oil revealed that the medium contains ionic clusters similar to more classical ionomers. These structural similarities are very helpful in understanding the chem. of mature oil paint binding media and the potential degrdn. mechanisms that affect oil paintings.
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    38. 38
      Silvester, G.; Burnstock, A.; Megens, L.; Learner, T.; Chiari, G.; van den Berg, K. J. A cause of water-sensitivity in modern oil paint films: the formation of magnesium sulphate. Stud. Conserv. 2014, 59, 38– 51,  DOI: 10.1179/2047058413y.0000000085
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      38
      A cause of water-sensitivity in modern oil paint films: The formation of magnesium sulphate
      Silvester, Genevieve; Burnstock, Aviva; Megens, Luc; Learner, Tom; Chiari, Giacomo; van den Berg, Klaas Jan
      Studies in Conservation (2014), 59 (1), 38-51CODEN: SCONAH; ISSN:0039-3630. (Maney Publishing)
      Unvarnished twentieth-century oil paintings are often sensitive to aq. swabbing, a method routinely employed by conservators for surface cleaning. This study proposes a connection between sensitivity and the presence of magnesium sulfate heptahydrate which has been identified on the surface of some of water-sensitive paintings. The probable source of magnesium is magnesium carbonate, an additive in some twentieth-century oil paints, which has reacted with atm. sulfur dioxide (SO2). Films made using modern manufd. paints and formulations made in the lab. were exposed to gaseous SO2 and raised relative humidity and examd. using SEM with energy dispersive X-ray spectroscopy and X-ray diffraction to characterize the cryst. entities. Films contg. magnesium carbonate formed magnesium sulphite and sulfate hydrates. Films contg. zinc oxide were also investigated. These formed zinc and sulfur contg. salts. Sensitivity to swabbing with water before and after exposure was evaluated. Films that developed salts, demonstrated increased sensitivity to aq. swabbing after exposure to SO2. Findings suggest that increased water sensitivity may be due to a combination of the formation of hygroscopic degrdn. products and to weakening of the paint film due to salt-induced disruption of the surface.
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    39. 39
      Zumbühl, S. The Rate of Solvent Action on Modern Oil Paint. Conservation of Modern Oil Paintings; Springer, 2019; pp 465– 474.
      Google Scholar
      There is no corresponding record for this reference.
    40. 40
      Sutherland, K. Solvent-extractable components of linseed oil paint films. Stud. Conserv. 2003, 48, 111– 135,  DOI: 10.1179/sic.2003.48.2.111
      Google Scholar
      40
      Solvent-extractable components of linseed oil paint films
      Sutherland, Ken
      Studies in Conservation (2003), 48 (2), 111-135CODEN: SCONAH; ISSN:0039-3630. (International Institute for Conservation of Historic and Artistic Works)
      As part of an investigation into the risks assocd. with the exposure of oil paintings to org. solvents in cleaning and other conservation treatments, the extn. of sol. org. components from a variety of pigmented oil films was studied. The extractable material was characterized using chromatog. anal. of extractable fatty acids. The influence on the leaching process of factors such as pigmentation and age of the paint films, and the type of solvent treatment, was examd. In addn. to lab.-prepd. paint films from three to 65 yr old, samples from paintings dating from as early as the thirteenth century were analyzed, to enable the data from the younger test films to be put in a more practical context. Expts. to measure the extent of leaching resulting from simulated cleaning treatments on paintings dating from the seventeenth to nineteenth centuries are also reported.
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    41. 41
      Astefanei, A.; van den Berg, K. J.; Burnstock, A.; Corthals, G. Surface Acoustic Wave Nebulization-Mass Spectrometry as a New Tool to Investigate the Water Sensitivity Behavior of 20th Century Oil Paints. J. Am. Soc. Mass Spectrom. 2021, 32, 444– 454,  DOI: 10.1021/jasms.0c00272
      Google Scholar
      41
      Surface Acoustic Wave Nebulization-Mass Spectrometry as a New Tool to Investigate the Water Sensitivity Behavior of 20th Century Oil Paints
      Astefanei, Alina; van den Berg, Klaas Jan; Burnstock, Aviva; Corthals, Garry
      Journal of the American Society for Mass Spectrometry (2021), 32 (2), 444-454CODEN: JAMSEF; ISSN:1879-1123. (American Chemical Society)
      The sensitive surfaces of many unvarnished 20th century oil paintings are of great concern for conservators and collection keepers. They may show degrdn. problems such as paint delamination, dripping, and soft and sticky paint and pose challenges for cleaning due to solvent sensitivity. We report for the first time the use of an innovative ambient ionization technique, surface acoustic wave nebulization-mass spectrometry (SAWN-MS), for the identification and characterization of fatty acids, dicarboxylic species and glycerides in water-sensitive modern oil paints. The compn. of 10 relevant Winsor and Newton 1964-1965 paint swatches that present different degrees of water sensitivity and two paint samples from a painting by the British artist Francis Bacon were studied. Principal component anal. was used for SAWN-MS data classification. Electrospray ionization (ESI)-MS was used as control method, specifically to compare the obtained ratios of markers of interest by the two ionization techniques. The results obtained by both ESI-MS and SAWN-MS are correlated and discussed in a broader context including the information on the oil media obtained by gas chromatog. (GC-MS) and also on the inorg. materials and salts characterized using a combination of methods in previous reports on samples from the same manufacturer. SAWN-MS was found to be a suitable tool for the detn. of sol. org. constituents present in the paints. The method provides an indication of the level of oxidn. and hydrolysis of the paint film by monitoring specific markers such as free palmitic and stearic acids, azelaic acid, monoacylglycerols, and diacylglycerols. The data showed that a higher level of water sensitivity coupled with a high level of oxidn. and hydrolysis is linked to higher dicarboxylic acid, diacyl- and triacylglyceride content and lower levels of short chain fatty acids. The data obtained by SAWN-MS provided a good correlation between the monitored species and the degree of water sensitivity.
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    42. 42
      Mayer, R. Artist’s Handbook of Materials and Techniques: Revised and Updated; Viking Books, 1991.
      Google Scholar
      There is no corresponding record for this reference.
    43. 43
      Roy, A. Artists’ Pigments. A Handbook of Their History and Characteristics; Archetype Publications Ltd., London, 1993; Vol. 2.
      Google Scholar
      There is no corresponding record for this reference.
    44. 44
      Harley, R. D. Artists’ Pigments, c. 1600–1835, a study in English documentary sources; Camelot Press, 1982.
      Google Scholar
      There is no corresponding record for this reference.
    45. 45
      Boon, J. J.; Hoogland, F.; Keune, K.; Parkin, H. M. Chemical processes in aged oil paints affecting metal soap migration and aggregation. AIC Paintings Specialty Group Postprints, Providence, Rhode Island , June 16–19, 2006; Vol. 19, pp 16– 23.
      Google Scholar
      There is no corresponding record for this reference.
    46. 46
      White, R. E.; Thomas, P. S.; Phillips, M. R.; Wuhrer, R. A DSC study of the effect of lead pigments on the drying of cold pressed linseed oil. J. Therm. Anal. Calorim. 2005, 80, 237– 239,  DOI: 10.1007/s10973-005-0642-5
      Google Scholar
      46
      A DSC study of the effect of lead pigments on the drying of cold pressed linseed oil
      White, R. E.; Thomas, P. S.; Phillips, M. R.; Wuhrer, R.
      Journal of Thermal Analysis and Calorimetry (2005), 80 (1), 237-239CODEN: JTACF7; ISSN:1388-6150. (Springer)
      Cold pressed linseed oil and paints prepd. using the inorg. pigments; lead white and red lead, were characterized using non-isothermal differential scanning calorimetry (DSC) in an air atm. to det. the effect of the pigment on the oxidative polymn. of the drying oil medium. For each paint sample, the onset temp. for oxidn. was reduced from 166° to the range 50 to 60° when a heating rate of 5 K min-1 was used. In order to det. the rate of drying, the non-isothermal expts. were carried out using a range of heating rates. A change in the mechanism oxidative polymn. was obsd. as the heating rate was increased.
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    47. 47
      Booth, D. G.; Dann, S. E.; Weller, M. T. The effect of the cation composition on the synthesis and properties of ultramarine blue. Dyes Pigm. 2003, 58, 73– 82,  DOI: 10.1016/s0143-7208(03)00037-8
      Google Scholar
      47
      The effect of the cation composition on the synthesis and properties of ultramarine blue
      Booth, D. G.; Dann, S. E.; Weller, M. T.
      Dyes and Pigments (2003), 58 (1), 73-82CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Science Ltd.)
      The effect of potassium cations on the shade of the ultramarine blue pigment system has been investigated by anal. of com. materials, ion exchange reactions of sodium-form ultramarine blue and a detailed study of the effect of adding potassium sources to ultramarine precursor mixts. Incorporation of potassium cations has the result of producing redder shade material, and the replacement of ∼20% of the sodium in the std. reaction mixt. produces the optimized red-shade pigment. The origin of this hue control may be a direct effect, involving interaction of potassium ions with the ultramarine blue structure and the S3- chromophore or, more likely, potassium ions aids the stabilization of S3- within the sodalite framework during the ultramarine blue formation process. In the com. process, the role of the potassium source in red shade formation may be performed by the incorporation of potassium-rich feldspar additives.
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    48. 48
      von Pettenkofer, M. über ölfarbe und Conservirung der GemÄlde-Gallerien durch das Regenerations-Verfahren; Vieweg, 1870.
      Google Scholar
      There is no corresponding record for this reference.
    49. 49
      Schnetz, K.; Gambardella, A. A.; van Elsas, R.; Rosier, J.; Steenwinkel, E. E.; Wallert, A.; Iedema, P. D.; Keune, K. Evidence for the catalytic properties of ultramarine pigment. J. Cult. Herit. 2020, 45, 25– 32,  DOI: 10.1016/j.culher.2020.04.002
      Google Scholar
      There is no corresponding record for this reference.
    50. 50
      Ogbobe, O.; Ossai, N. N. Effect of colour on the mechanical and chemical properties of naturally photooxidized high density polyethylene. Acta Polym. 1992, 43, 173– 176,  DOI: 10.1002/actp.1992.010430308
      Google Scholar
      50
      Effect of color on the mechanical and chemical properties of naturally photooxidized high-density polyethylene
      Ogbobe, O.; Ossai. N. N.
      Acta Polymerica (1992), 43 (3), 173-6CODEN: ACPODY; ISSN:0323-7648.
      The effect of color on the mech. and chem. properties of colored HDPE at photooxidn. by natural sunlight is studied. The extent of polymer deterioration depends on the nature of the applied pigments.
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    51. 51
      Iwu, C. F.; Egbuhuzor, M. Oxidative Photodegradation of Colored LLDPE, ANTEC-Conference Proceedings , 2004; pp 3559– 3563.
      Google Scholar
      There is no corresponding record for this reference.
    52. 52
      Bonaduce, I.; Carlyle, L.; Colombini, M. P.; Duce, C.; Ferrari, C.; Ribechini, E.; Selleri, P.; Tiné, M. R. New Insights into the Ageing of Linseed Oil Paint Binder: A Qualitative and Quantitative Analytical Study. PLoS One 2012, 7, e49333  DOI: 10.1371/journal.pone.0049333
      Google Scholar
      52
      New insights into the ageing of linseed oil paint binder: a qualitative and quantitative analytical study
      Bonaduce, Ilaria; Carlyle, Leslie; Colombini, Maria Perla; Duce, Celia; Ferrari, Carlo; Ribechini, Erika; Selleri, Paola; Tine, Maria Rosaria
      PLoS One (2012), 7 (11), e49333CODEN: POLNCL; ISSN:1932-6203. (Public Library of Science)
      This paper presents an anal. investigation of paint reconstructions prepd. with linseed oil that have undergone typical 19th century treatments in prepn. for painting. The oil was mech. extd. from the same seed lot, which was then processed by various methods: water washing, heat treatments, and the addn. of driers, with and without heat. A modern process lead white (Dutch source, Schoonhoven) and a com. available vine black were used as pigments. The reconstructions were prepd. in 1999, and naturally aged from then onwards. We compared thermogravimetric anal. (TG), which yields macromol. information, with gas chromatog.-mass spectrometry (GC-MS) and direct exposure mass spectrometry (DEMS), which both provide mol. information. The study enabled us to quant. demonstrate, for the first time, that the parameters used to identify drying oils are deeply influenced by the history of the paint. In particular, here we show that the ratio between the relative amts. of palmitic and stearic acid (P/S), which is used as an index for differentiating between drying oils, is extremely dependent on the pigments present and the age of the paint. Moreover the study revealed that neither the P/S parameter nor the ratios between the relative amts. of the various dicarboxylic acids (azelaic over suberic and azelaic over sebacic) can be used to trace the sorts of pre-treatment undergone by the oil investigated in this study. The final results represent an important milestone for the scientific community working in the field, highlighting that further research is still necessary to solve the identification of drying oils in works of art.
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    53. 53
      Bonaduce, I.; Carlyle, L.; Colombini, M. P.; Duce, C.; Ferrari, C.; Ribechini, E.; Selleri, P.; Tiné, M. R. A multi-analytical approach to studying binding media in oil paintings: Characterisation of differently pre-treated linseed oil by DE-MS, TG and GC/MS. J. Therm. Anal. Calorim. 2012, 107, 1055– 1066,  DOI: 10.1007/s10973-011-1586-6
      Google Scholar
      53
      A multi-analytical approach to studying binding media in oil paintings
      Bonaduce, Ilaria; Carlyle, Leslie; Colombini, Maria Perla; Duce, Celia; Ferrari, Carlo; Ribechini, Erika; Selleri, Paola; Tine, Maria Rosaria
      Journal of Thermal Analysis and Calorimetry (2012), 107 (3), 1055-1066CODEN: JTACF7; ISSN:1388-6150. (Akademiai Kiado)
      This article presents a multi-anal. approach to investigating the drying, polymn. and oxidative degrdn. of linseed oil, which had undergone various treatments known to be undertaken during the nineteenth century in prepn. for painting. The oil was mech. extd. from the same seed lot then processed by different methods: water washing, heat treatments, and the addn. of driers, with and without heat. The oil was prepd. in 1999 within the framework of the MOLART project. We compared thermogravimetric anal. (TG), which yields macromol. information, with gas-chromatog. mass-spectrometry (GC/MS) and direct exposure mass spectrometry (DE-MS), which provide mol. information. This comparison enabled us to elucidate the role of pre-treatment on the compn. of the oil. TG and oxygen uptake curves registered at a const. temp. helped us to identify the different phys. behavior of the oil samples, thus highlighting the presence of hydrolyzed, oxidized and crosslinked fractions, as a consequence of the different pre-treatments. GC/MS was used to characterize the sol. and non-polymeric fraction of the oil, to calc. the ratios of palmitic to stearic acid (P/S), and azelaic to palmitic acid (A/P), and to further evaluate the effects of oil pre-treatments. DE-MS using chem. ionization with CH4, enabled us to establish the chem. compn. of the oil in different stages of ageing. DE-MS proved to be a useful tool for a simultaneous semi-quant. characterization of the free fatty acids, monoglycerides, diglycerides and triglycerides present in each sample. The combination of thermal anal. with GC/MS and DE-MS enabled a model to be developed, which unravelled how oil pre-treatments produce binders with different phys.-chem. qualities.
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    54. 54
      Dubrulle, L.; Lebeuf, R.; Thomas, L.; Fressancourt-Collinet, M.; Nardello-Rataj, V. Catalytic activity of primary and secondary driers towards the oxidation and hydroperoxide decomposition steps for the chemical drying of alkyd resin. Prog. Org. Coat. 2017, 104, 141– 151,  DOI: 10.1016/j.porgcoat.2016.12.018
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      54
      Catalytic activity of primary and secondary driers towards the oxidation and hydroperoxide decomposition steps for the chemical drying of alkyd resin
      Dubrulle, L.; Lebeuf, R.; Thomas, L.; Fressancourt-Collinet, M.; Nardello-Rataj, V.
      Progress in Organic Coatings (2017), 104 (), 141-151CODEN: POGCAT; ISSN:0300-9440. (Elsevier B.V.)
      The autoxidn. of fatty acid Me esters (FAMEs) derived from colza, sunflower, linseed and tung oils and the oxidn. of sunflower FAMEs in the presence of several com. driers based on Co(II), Mn(II), Fe(II), V(IV), Sr(II), Zr(IV), Ca(II), Zn(II) have been investigated. The oxidn. step was studied through oxygen uptake measurements with an automatic O2 pressure recorder (RapidOxy) and by ATR-FTIR spectroscopy. Pure Me linoleate hydroperoxides (ROOH) were prepd. by photooxidn. to follow their decompn. by HPLC in the presence of the driers. Only Co(II), Mn(II) and Fe(II) as primary driers have catalytic effects both on the oxidn. and on the ROOH decompn. steps. However, the Co-based drier shows the higher oxidn. rate while the Fe-based drier has the greater ROOH decompn. rate. On the other hand, oxidn. runs faster by increasing the amt. of driers from 2.5 to 25-50 mM but an antioxidant behavior is obsd. at higher levels. Secondary driers show poor or no catalytic activities both on the oxidn. and the ROOH decompn. steps with a conversion ranging from 5 to 9% over 24 h. Combinations of driers were finally investigated to highlight possible synergistic or antagonist effects during the oxidn. and hydroperoxides decompn. steps. Synergistic effects were found only on the oxidn. stage with Co(II)-Zn(II), Mn(II)-Zn(II) and Fe(II)-Ca(II), while these latter do not have influence on the decompn. step.
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    55. 55
      Tamburini, D.; Sardi, D.; Spepi, A.; Duce, C.; Tinè, M. R.; Colombini, M. P.; Bonaduce, I. An investigation into the curing of urushi and tung oil films by thermoanalytical and mass spectrometric techniques. Polym. Degrad. Stab. 2016, 134, 251– 264,  DOI: 10.1016/j.polymdegradstab.2016.10.015
      Google Scholar
      55
      An investigation into the curing of urushi and tung oil films by thermoanalytical and mass spectrometric techniques
      Tamburini, Diego; Sardi, Dario; Spepi, Alessio; Duce, Celia; Tine, Maria Rosaria; Colombini, Maria Perla; Bonaduce, Ilaria
      Polymer Degradation and Stability (2016), 134 (), 251-264CODEN: PDSTDW; ISSN:0141-3910. (Elsevier Ltd.)
      Urushi is the oldest and most precious lacquer used since antiquity in East Asia. For artistic purposes, to obtain suitable rheol. properties, the lacquer is usually mixed with a vegetable oil. In this work we studied the curing process of urushi/tung oil mixts. to highlight the chem. interactions at the mol. level between the two materials. A multi-anal. approach was adopted, based on thermogravimetry (TG), differential scanning calorimetry (DSC), gas chromatog.-mass spectrometry (GC-MS), evolved gas anal.-mass spectrometry (EGA-MS), anal. pyrolysis coupled with gas chromatog. and mass spectrometry (Py-GC-MS) and high performance liq. chromatog.-mass spectrometry (HPLC-MS). Fresh and aged mixts. were analyzed and the results were compared with those obtained from the anal. of the individual materials. The data highlighted that different polymn. and oxidn. mechanisms take place in oil/urushi mixts. compared to the pure materials. Py-GC-MS and GC-MS showed that the profile of aliph. mono- and di-carboxylic acids was drastically different for the aged film of pure tung oil compared to the mixts. The ratio between the relative content of azelaic and palmitic acids was much lower in the mixts. than in the pure oil, highlighting a lower level of oxidn. The relative content of short chain carboxylic acids, which are produced by pyrolysis of the crosslinked oil network, increased as the concn. of urushi in the mixts. increased, thus indicating an increasing level of reticulation. HPLC-MS showed a relatively higher amt. of triglycerides with hydroxylated fatty acids - the intermediate oxidn. product of polyunsatd. fatty acids - in the mixts. with respect to pure tung oil.
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    56. 56
      Frankel, E. N. Volatile lipid oxidation products. Prog. Lipid Res. 1983, 22, 1– 33,  DOI: 10.1016/0163-7827(83)90002-4
      Google Scholar
      56
      Volatile lipid oxidation products
      Frankel, E. N.
      Progress in Lipid Research (1983), 22 (1), 1-33CODEN: PLIRDW; ISSN:0163-7827.
      A review with 222 refs. on the formation of volatile flavor- and odor-related compds. in food during oxidative lipid deterioration.
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    57. 57
      Hess, P. S.; O’Hare, G. A. Oxidation of linseed oil. Ind. Eng. Chem. 1950, 42, 1424– 1431,  DOI: 10.1021/ie50487a044
      Google Scholar
      57
      Oxidation of linseed oil. Temperature effects
      Hess, P. S.; O'Hare, G. A.
      Industrial and Engineering Chemistry (1950), 42 (), 1424-31CODEN: IECHAD; ISSN:0019-7866.
      The effects exerted by differences in reaction temp. on induction period and on bulk oxypolymerization of raw linseed oil under otherwise const. conditions of air flow and agitation are discussed. At 84-200° the initial viscosity increase rate is identical for all temps. At a definite point in the oxidation a change occurs in the viscosity increase rate, making it possible to show at least 3 distinct temp. regions (above 130°, 84-130°, and below 84°), each characterized by different types of oxidative changes. In the intermediate temp. range the length of the induction period decreases exponentially with unit increase in temp.; the induction period is of very short duration at 130° and above. During the initial stages of oxypolymerization the peroxide value increase is independent of the temp. in the 84-200° range; the max. value, however, is a definite function of temp., higher values corresponding to lower reaction temps. Ultraviolet absorption analyses indicate that the formation of diconjugated systems reaches a max. and that at 84-200° the diene configuration as detd. by the characteristic inflection at 232 mμ is never appreciably greater than 5%; higher values are obtained at lower reaction temps. The results obtained in this study agree with the free radical propagation theory of oil oxidation and appear to indicate the formation of an intermediate prior to oxidative mol. wt. build-up. This intermediate may be of the chelate type and oxidative mol. wt. increases may take place partially by assocn. of intermediates to double mols. by H bonding.
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    58. 58
      Labuza, T. P.; Dugan, L. R., Jr. Kinetics of lipid oxidation in foods. Crit. Rev. Food Sci. Nutr. 1971, 2, 355– 405,  DOI: 10.1080/10408397109527127
      Google Scholar
      There is no corresponding record for this reference.
    59. 59
      Chan, H. S. The mechanism of autoxidation. Autoxidation of Unsaturated Lipids; Academia Press, 1987.
      Google Scholar
      There is no corresponding record for this reference.
    60. 60
      Ghnimi, S.; Budilarto, E.; Kamal-Eldin, A. The new paradigm for lipid oxidation and insights to microencapsulation of Omega-3 fatty acids. Compr. Rev. Food Sci. Food Saf. 2017, 16, 1206– 1218,  DOI: 10.1111/1541-4337.12300
      Google Scholar
      60
      The New Paradigm for Lipid Oxidation and Insights to Microencapsulation of Omega-3 Fatty Acids
      Ghnimi, Sami; Budilarto, Elisabeth; Kamal-Eldin, Afaf
      Comprehensive Reviews in Food Science and Food Safety (2017), 16 (6), 1206-1218CODEN: CRFSBJ; ISSN:1541-4337. (Institute of Food Technologists)
      The consumption of omega-3 fatty acids provides a wide range of health benefits. However, the incorporation of these fatty acids in foods is limited because of their high oxidative instability. A new paradigm has emerged to better explain the oxidn. mechanism of polyunsatd. fatty acids, which will be discussed here with ref. to bulk lipids considered a special case of water in oil microemulsion. This paradigm suggests that lipid oxidn. reactions are initiated by heterogeneous catalysis by metal oxides followed by the formation of micelles contg. initial hydroperoxides, water, and other amphiphilic compds. The induction period comes to the end when the formed micelles reach a crit. micelle concn. and start to decomp. opening the way to intense free radical reactions. Antioxidants and synergists extend the induction period not only by scavenging free radicals but also by stabilizing the micelles. With better understanding of the lipid oxidn. mechanism, a tailored choice of antioxidants and synergistic combinations, and efficient encapsulation methods may be optimized to provide stable encapsulates contg. highly n-3 polyunsatd. fatty acids. Smart processing and encapsulation technologies utilizing properly stabilized oils as well as optimized packaging parameters aiming to enhance n-3 fatty acid stability by smart selection/design of antioxidants, control of the interfacial physics and chem., and elimination of surface oil are needed for this purpose.
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    61. 61
      Thomas, A.; Matthäus, B.; Fiebig, H. J. Fats and fatty oils. Ullmann’s Encyclopedia of Industrial Chemistry; Wiley-VCH, 2000; pp 1– 84.
      Google Scholar
      There is no corresponding record for this reference.
    62. 62
      Xia, W.; Budge, S. M. Techniques for the Analysis of Minor Lipid Oxidation Products Derived from Triacylglycerols: Epoxides, Alcohols, and Ketones. Compr. Rev. Food Sci. Food Saf. 2017, 16, 735– 758,  DOI: 10.1111/1541-4337.12276
      Google Scholar
      62
      Techniques for the Analysis of Minor Lipid Oxidation Products Derived from Triacylglycerols: Epoxides, Alcohols, and Ketones
      Xia, Wei; Budge, Suzanne M.
      Comprehensive Reviews in Food Science and Food Safety (2017), 16 (4), 735-758CODEN: CRFSBJ; ISSN:1541-4337. (Institute of Food Technologists)
      Lipid oxidn. can lead to flavor and safety issues in fat-contg. foods. In order to measure the extent of lipid oxidn., hydroperoxides and their scission products are normally targeted for anal. purposes. In recent years, the formation of rarely monitored oxygenated products, including epoxides, alcs., and ketones, has also raised concerns. These products are thought to form from alternative pathways that compete with chain scissions, and should not be neglected. In this review, a no. of instrumental techniques and approaches to det. epoxides, alcs., and ketones are discussed, with a focus on their selectivity and sensitivity in applications to food lipids and oils. Special attention is given to methods employing gas chromatog. (GC), high-performance liq. chromatog. (HPLC), and NMR (NMR). For characterization purposes, GC-mass spectrometry (GC-MS) provides valuable information regarding the structures of individual oxygenated fatty acids, typically as Me esters, isolated from oxygenated triacylglycerols (TAGs), while the use of liq. chromatog.-MS (LC-MS) techniques allows anal. of intact oxygenated TAGs and offers information about the position of the oxygenated acyl chain on the glycerol backbone. For quant. purposes, traditional chromatog. methods have exhibited excellent sensitivity, while spectroscopic methods, including NMR, are superior to chromatog. for their rapid anal. cycles. Future studies should focus on the development of a routine quant. method that is both selective and sensitive.
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    63. 63
      Duce, C.; Bernazzani, L.; Bramanti, E.; Spepi, A.; Colombini, M. P.; Tiné, M. R. Alkyd artists’ paints: Do pigments affect the stability of the resin? A TG and DSC study on fast-drying oil colours. Polym. Degrad. Stab. 2014, 105, 48– 58,  DOI: 10.1016/j.polymdegradstab.2014.03.035
      Google Scholar
      63
      Alkyd artists' paints: Do pigments affect the stability of the resin? A TG and DSC study on fast-drying oil colours
      Duce, C.; Bernazzani, L.; Bramanti, E.; Spepi, A.; Colombini, M. P.; Tine, M. R.
      Polymer Degradation and Stability (2014), 105 (), 48-58CODEN: PDSTDW; ISSN:0141-3910. (Elsevier Ltd.)
      We studied ten alkyd artists' paints from the Griffin Alkyd, "fast drying oil colors" series (Winsor & Newton) in order to evaluate the effect of pigment-binder interactions on the stability of the alkyd resin. The literature on alkyd paints has focused above all on the characterization of the paints and their ageing processes using various techniques, however, to the best of our knowledge, research on pigment-resin interaction is still lacking. We selected four alkyd colors (red, blue, yellow and green) in two formulations based on inorg. or org. pigments together with titanium white and black formulated with carbonized bones and we applied a combined differential scanning calorimetric (DSC) and thermogravimetric (TG) approach. The pure pigments and the whole paint replicas were analyzed, and the effect of natural ageing on the paints was monitored for eight months. Artificial ageing in an acetic acid atm. was also studied. We found that org. and metallorg. pigments interacted the strongest with the alkyd resin, while the inorg. pigments appear to act more as dispersants. The chem. drying of the paint on the other hand, via auto-oxidn., is almost independent of the pigment and only depends on the alkyd content. The paint is fully dried after eight months. Paint samples from two hyper-realistic artworks, "Salto di qualita´", 2003, and "Senza nome", 2007, by the Italian painter Patrizia Zara were investigated by DSC in order to evaluate the effects of several years of natural ageing on alkyd fast-drying oil colors. At the end of chem. drying, the alkyd colors seemed very stable. Artificial acid ageing visibly damaged the paint replicas, but appeared to act mostly on the pigment rather than on the resin network.
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    64. 64
      Ploeger, R.; Scalarone, D.; Chiantore, O. The characterization of commercial artists’ alkyd paints. J. Cult. Herit. 2008, 9, 412– 419,  DOI: 10.1016/j.culher.2008.01.007
      Google Scholar
      There is no corresponding record for this reference.
    65. 65
      Mallégol, J.; Gonon, L.; Commereuc, S.; Verney, V. Thermal (DSC) and chemical (iodometric titration) methods for peroxides measurements in order to monitor drying extent of alkyd resins. Prog. Org. Coat. 2001, 41, 171– 176,  DOI: 10.1016/s0300-9440(01)00144-8
      Google Scholar
      65
      Thermal (DSC) and chemical (iodometric titration) methods for peroxides measurements in order to monitor drying extent of alkyd resins
      Mallegol, J.; Gonon, L.; Commereuc, S.; Verney, V.
      Progress in Organic Coatings (2001), 41 (1-3), 171-176CODEN: POGCAT; ISSN:0300-9440. (Elsevier Science S.A.)
      Calcn. of the peroxide value of an oxidizing coating appears to be the best way of evaluating the drying extent. For instance, indentation hardness can be measured as an indication of the extent of cure, but it can bring no information about further potential evolution of the network that may occur whether there are still peroxides. Iodometry and DSC have proven to be valuable methods for the detn. of peroxide concn. in oil-based coatings. For a given substrate involved in the oxidn. reaction, such as drying oil in this study, this heat of reaction can be considered as const. but introduction of a drier can increase this energy by lowering decompn. energy of peroxides. We have also obsd. that in systems different from drying oils, the heat of reaction can be very modified when radicals produced by peroxide decompn. react on different unsatd. chains. DSC has shown to be a potential method of differentiating types of peroxide decompn. (monomol. or bimol.). The occurrence of each type of decompn. measured by peak deconvolution may become a very useful tool in the detn. of oxidn. mechanisms in polymeric coatings submitted to thermo- or photo-ageing.
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    66. 66
      Eglinton, G.; Hunneman, D. H.; McCormick, A. Gas chromatographic-mass spectrometric studies of long chain hydroxy acids.-III.1 The mass spectra of the methyl esters trimethylsilyl ethers of aliphatic hydroxy acids. A facile method of double bond location. Org. Mass Spectrom. 1968, 1, 593– 611,  DOI: 10.1002/oms.1210010413
      Google Scholar
      66
      Gas chromatographic--mass spectrometric studies of long chain hydroxy acids. III. The mass spectra of the methyl esters trimethylsilyl ethers of aliphatic hydroxy acids. A facile method of double bond location
      Eglinton, Geoffrey; Hunneman, D. H.; McCormick, Andrew
      Organic Mass Spectrometry (1968), 1 (4), 593-611CODEN: ORMSBG; ISSN:0030-493X.
      Trimethylsilylation has proved to be extremely useful in the gas chromatog. and the mass spectrometry of hydroxy acid methyl esters. The characteristic mass spectral fragmentation patterns have shown these derivs. to be superior in some respects to others for structural elucidation; in particular, hydroxylation followed by trimethylsilylation provides a useful method of double bond location in unsatd. fatty acid esters.
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    67. 67
      Chiavari, G.; Fabbri, D.; Prati, S. Effect of pigments on the analysis of fatty acids in siccative oils by pyrolysis methylation and silylation. J. Anal. Appl. Pyrolysis 2005, 74, 39– 44,  DOI: 10.1016/j.jaap.2004.11.013
      Google Scholar
      67
      Effect of pigments on the analysis of fatty acids in siccative oils by pyrolysis methylation and silylation
      Chiavari, Giuseppe; Fabbri, Daniele; Prati, Silvia
      Journal of Analytical and Applied Pyrolysis (2005), 74 (1-2), 39-44CODEN: JAAPDD; ISSN:0165-2370. (Elsevier B.V.)
      The relative abundance of the dicarboxylic acids azelaic (nonanedioic) and suberic (octanedioic) with respect to monocarboxylic fatty acids is diagnostic for the identification of siccative oils in painting layers. Fatty acids can be produced from the sample by thermal (pyrolysis) and/or chem. (hydrolysis) degrdn., and then detd. by gas chromatog.-mass spectrometry (GC-MS) in the form of Me or trimethylsilyl (TMS) ester derivs. However, the presence of matrix components in the layer (e.g. pigments) might interfere with the anal. procedure. In this study, the presence of three inorg. pigments (cinnabar (HgS), lead white (2PbCO3·Pb(OH)2) and zinc white (ZnO)) in linseed oil layers was investigated in relation to the detn. of fatty acids by anal. pyrolysis with in situ derivatization. Two methods were applied: pyrolysis/methylation with tetramethylammonium hydroxide (TMAH) and pyrolysis/silylation with hexamethyldisilazane (HMDS), both in combination with online GC-MS. Pyrolysis/methylation and, to a lesser extent, pyrolysis/silylation were influenced by the presence of the pigments which caused a significant decrease in the relative content of azelaic acid. Discriminating siccative oil from egg tempera might be problematic in the presence of lead white and zinc white. Reactive pyrolysis-GC-MS was compared with the classical wet method (alk. hydrolysis, silylation, GC-MS anal.) and the effect of sample prepn. was considered.
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    68. 68
      Rosi, F.; Cartechini, L.; Monico, L.; Gabrieli, F.; Vagnini, M.; Buti, D.; Doherty, B.; Anselmi, C.; Brunetti, B. G.; Miliani, C. Tracking metal oxalates and carboxylates on painting surfaces by non-invasive reflection mid-FTIR spectroscopy. Metal Soaps in Art; Springer, 2019; pp 173– 193.
      Google Scholar
      There is no corresponding record for this reference.
    69. 69
      Bordignon, F.; Postorino, P.; Dore, P.; Tabasso, M. L. The formation of metal oxalates in the painted layers of a medieval polychrome on stone, as revealed by micro-Raman spectroscopy. Stud. Conserv. 2008, 53, 158– 169,  DOI: 10.1179/sic.2008.53.3.158
      Google Scholar
      69
      The formation of metal oxalates in the painted layers of a medieval polychrome on stone, as revealed by micro-Raman spectroscopy
      Bordignon, Francesca; Postorino, Paolo; Dore, Paolo; Tabasso, Marisa Laurenzi
      Studies in Conservation (2008), 53 (3), 158-169CODEN: SCONAH; ISSN:0039-3630. (International Institute for Conservation of Historic and Artistic Works)
      This paper reports a detailed study of the degrdn. phenomena exhibited by the painted bas-relief sculpture on the portal of the Basilica of San Zeno Maggiore in Verona. This study extends the wide diagnostic project started previously by the Istituto Centrale per il Restauro (ICR, Rome). Micro-Raman measurements on polished cross-sections of samples from the painted lunette allowed detailed identification of the species present in the different layers, thanks to the high spatial resoln. and chem. selectivity of this technique. One of the most interesting findings was the occurrence of large amts. of metal oxalates. In particular, in addn. to calcium oxalates, copper oxalate was obsd. in layers contg. copper-based pigments, and data on the distribution of both these oxalates within the painted layers were obtained. The results give evidence of the nature of the degrdn. processes taking place involving the painting materials, provide information about the degree of degrdn., and make it possible to advance reliable hypotheses on the causes and mechanisms of ageing. Along with calcium oxalates, copper oxalate proves to be a reliable marker for degrdn., which is of general interest for the study of outdoor paintings contg. copper-based pigments.
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    70. 70
      van Loon, A.; Gambardella, A. A.; Gonzalez, V.; Cotte, M.; De Nolf, W.; Keune, K.; Leonhardt, E.; de Groot, S.; Gaibor, A. N. P.; Vandivere, A. Out of the blue: Vermeer’s use of ultramarine in Girl with a Pearl Earring. Heritage Sci. 2020, 8, 25,  DOI: 10.1186/s40494-020-00364-5
      Google Scholar
      There is no corresponding record for this reference.

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    The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsapm.0c01441.

    • Experimental and fitted oxygen uptake profiles of linseed oil obtained by the equation with only one exponential and by eq 1; experimental and fitted oxygen uptake profiles of oils and model oil paints by eq 1; DSC curves of oils and model oil paints; Tonset, Tpeak of the normalized DSC curves for oils and model oil paints; list of compounds identified as trimethylsilyl derivatives in the chromatograms obtained by GC–MS and Py–GC–MS of model oil paints; total ion chromatograms obtained by GC–MS analysis of model oil paints; mass spectra of α- and β-hydroxyacids obtained with GC–MS; extracted ion pyrograms of m/z 129 of model oil paints; and mass spectra attributed to 8-hydroxydec-9-enoic acid, 8-hydroxyundec-10-enoic acid and 9-hydroxyoctadec-12-enoic acid obtained with Py–GC–MS (PDF)


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