Interaction of PMMA-silica in PMMA-silica hybrids under acid catalyst and catalyst-less conditions

PMMA-silica hybrids were prepared by the sol-gel process polymerization from methyl methacrylate (MMA) and tetraethyl orthosilicate (TEOS) and hydroxypropyl acrylate (HPA). The mechanisms of interaction between the organic PMMA and inorganic silica in the PMMA-silica hybrids prepared under acid catalyst and catalyst-less conditions were analyzed by Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). By FTIR absorption spectra, and XPS spectrum analyses, it was found that the covalent bond (Si-O-C) between the organic component and the inorganic component was formed even under catalyst-less condition. The catalyst had a great influence on yielding Si-O-C bonds.The ratio of the covalent bond, Si-O-C, between the organic component and the inorganic component under the acid catalyst condition was higher than that under the catalyst-less condition. With the results of FTIR and XPS analyses, a chemical reaction process was made clear and with this process the differences of the recation vecocitry, the formation of Si-O-Si bonds and Si-O-C bonds and their amount under the acid catalyst condition and/or catalyst-less condition could be predicted quantatively.