Web Release Date: December 12,
Beneficial Effect of Nanoclay in Atom Transfer Radical Polymerization of Ethyl Acrylate: A One Pot Preparation of Tailor-Made Polymer Nanocomposite
Rubber Technology Centre, Indian Institute of Technology, Kharagpur, 721302, India
Received July 10, 2007
Revised Manuscript Received September 27, 2007
Abstract:
The atom transfer radical polymerization (ATRP) of ethyl acrylate (EA) was carried out in bulk
at 90 
C in the presence of organically modified nanoclay as an additive. A remarkable enhancement in the rate
of polymerization was observed and it was compared with the ATRP of EA without nanoclay. Time of dispersion
of clay in monomer (td) prior to polymerization and the extent of clay loading were found to have a positive
effect on polymerization rate. The polymerization proceeded through first-order kinetics and molecular weights
increased linearly with conversion, close to the targeted molecular weights. The living nature of the end group
was confirmed by MALDI-TOF-mass spectrometry and a chain extension experiment. Several factors may account
for this unexpectedly rapid, yet controlled ATRP of EA in the presence of nanoclay additive. Fourier transform
infrared spectroscopy (FTIR), nuclear magnetic resonance spectrometry (NMR), and dynamic mechanical thermal
analysis (DMTA) studies showed that the added nanoclay interacts with the carbonyl group (>C=O) of the
monomer and reduces the electron density in the conjugated C=C bond, thereby increasing the reactivity of the
monomer. This particular interaction also has an effect in the dynamic equilibrium of activation-deactivation
cycle in ATRP. Interestingly, the resulting nanocomposites had exfoliated clay particles, as evident from wide-angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM) studies.
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