Organic-inorganic hybrid materials. V. Dynamics and degradation of poly(methyl methacrylate) silica hybrids

Abstract

Poly(methyl methacrylate)–silica hybrid materials (PMMA–SiO2) were prepared by in situ polycondensation of alkoxysilane in the presence of trialkoxysilane-functional PMMA. Infrared, differential scanning calorimetry, 29Si and 13C nuclear magnetic resonance spectroscopy, and thermogravimetric analysis were used to study the PMMA–SiO2 hybrids. The effects of the content and kind of the alkoxysilane on the dynamics and stability of the PMMA–SiO2 hybrids were investigated in this study.The dynamics of SiO2within hybrids were investigated with 29Si–1H cross-polarization. The spin-diffusion path length was on a nanometer scale estimated with the spin–lattice relaxation time in the rotating frame (T). The apparent activation energies for the degradation of the hybrids under air and nitrogen were evaluated by the van Krevelen method. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1972–1980, 2000