Study on the synthesis and thermal degradation of vinylphenylpolysilsesquioxane

Vinylphenylpolysilsesquioxane is synthesized through hydrolysis and condensation method, using phenyltrimethoxysilane and dimethylvinylethyoxysilane as raw materials. Its structure is confirmed by Fourier-transformed infrared (FTIR) and nuclear magnetic resonance (NMR) spectra. The degradation of vinylphenylpolysilsesquioxane under nitrogen atmosphere is investigated by thermal analysis techniques combined with infrared spectroscopy (TGA-FTIR) and TGA combined with gas chromatograph-mass spectrometer (TG-GC-MS). Its thermal degradation kinetics and thermal degradation mechanism is inferred from TGA under nitrogen atmosphere. In the light of these analyses, the degradation process is divided into two stages. In the first stage from 170 °C to 465 °C, the thermal degradation products are oligomer polysilsesquioxane, a little CO2 and H2O. Its thermal degradation mechanism is nucleation and growth process, its reaction order was 4. Its thermal degradation kinetics equation is dαdt=3.25×1017(1−α)[−ln(1−α)]−3exp(−2.73×104/T).In the second stage, the thermal degradation products are benzene and its derivatives. Its thermal degradation mechanism is nucleation and growth process, its reaction order was 4. Its thermal degradation kinetics equation isdαdt=5.37×1015(1−α)[−ln(1−α)]−3exp(−3.60×104/T).