Ultra-High Performance of Nano-Engineered Graphene-Based Natural Jute Fiber Composites

Natural fibers composites are considered as sustainable alternative to synthetic composites due to their environmental and economic benefits. However, they suffer from poor mechanical and interfacial properties due to a random fiber orientation and weak fiber-matrix interface. Here we report nano-engineered graphene-based natural jute fiber preforms with a new fiber architecture (NFA) which significantly improves their properties and performances. Our graphene-based NFA of jute fiber perform enhances Young modulus of jute-epoxy composites by ~324% and tensile strength by ~110% more than untreated jute fiber composites, by arranging fibers in parallel direction through individualisation and nano surface engineering with graphene derivatives. This could potentially lead to manufacturing of high performance natural alternatives to synthetic composites in various stiffness driven high performance applications.


Supporting Information 2: Preparation of Jute and Glass Fibre Preform
shows the fibrillated preform obtained before and after hand combing. Figure S2a shows the sliver bundles cut into 300 mm in size to process. After combing we arranged the fibrillated fibres in unidirectional so that the fibres are parallel to each other ( Figure S2b). In order to coat the jute fibre preform with graphene oxides, we first collected the fibrillated fibre. We then sealed the edge of fibre with both sided tape so that fibre alignment never change after the coating ( Figure S3a). Following this, we slowly dipped the preform into the coating solution bath and left for 30 mins time, allowing enough time so that the fibres are homogenously coated. Fibres remained into the coating solutions can be found in the ( Figure   S3b).   Figure S4 shows the digital image of manufacturing glass fibre preform and its composites.
We placed the glass fibre roving parallel to each other with the help of pinboard to obtain UD glass fibre preform. Flash tape was used to hold the fibre together as shown in the Figure S4a.
We then carefully collected the UD preform and made the composites ( Figure S4b) by vacuum infusion process.    Optical microscopy was used to qualitatively measure the image of fibre packing arrangement and porosity of the composites. For doing this, three sections from each of the composites were cast by using epoxy resin (resin to hardener ratio 100:10 by mass) and cured for 48 hrs.

Supporting Information 4: Microscopy and Density of the Composites
The samples were ground (using 240, 400, 600, 800, 1200 grit paper) and polished by using diamond grit paper of 6µ and followed by 1µ the samples were polished. Finally, the polished samples were viewed under a microscope (Keyence digital microscope VHX-500F, UK) with 500x magnification. Images were processed using ImageJ software. We conduct tensile test of the composites based on ASTM-D3039 standard. We use specimen protector in order to protect the specimen from damage. We use pressure bar to grip the specimen and a video camera to measure the strain of the composites.   Figure S7 provides the specimen used in the longitudinal tensile test of jute fibre/epoxy composites. After the tensile test G0.75 coated composites ( Figure S7) shows fibre splitting instead of catastrophic failure due to the strong interface between the GO coated jute fibre and epoxy matrix. On the other hand uncoated (UT) specimen have catastrophic failure mode in the tensile test ( Figure S7).    Figure S9. This reduction is due to the breaking of a hydrogen bond between the O-H groups of cellulose and hemicellulose molecules. Peaks at 1742 and 1242 cm -1 are assigned to C=O and C-O stretching modes respectively and are present in the graphs of the UT and HA fibres.
The peak at 1742 cm -1 is the characteristic peak for the carbonyl stretch of carboxylic groups in hemicellulose and pectin. The peak at 1242 cm -1 corresponds to C-O stretching in the acetyl groups in hemicellulose. Following alkali treatment of the fibres, HA0.5 do not provide either of the two peaks. The disappearance of these two peaks after alkali treatment indicates that either the carboxylic acid and acetyl groups were removed or dissolved by the alkali solutions.