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.