Organic-inorganic hybrid materials 7: characterization and degradation of polyvinylimidazole-silica hybrids

Polyvinylimidazole-silica hybrid materials (PVI-SiO2) containing various proportions of covalently bonded silica were prepared from [3-(methacryloxy)propyl] trimethoxysilane modified polyvinylimidazole (PVI), water and tetramethoxysilane (TMOS) via a sol-gel technique. Infrared (IR), Si-29 and C-13 nuclear magnetic resonance (NMR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to analyse the structures and properties of hybrids with various proportions of TMOS. The apparent activation energies E-u for desorption of water and decomposition of PVI chains in hydroxylated hybrids were respectively around 55 and 35 kJ/mol, while the values were increased by about 10 kJ/mol in dehydroxylated hybrids. (C) 2000 Elsevier Science Ltd. All rights reserved.