Thermal decomposition of poly(methylphenylsilane)

The thermal decomposition of poly(methylphenylsilane) was performed at cons tant heating rates and isothermal conditions. The evolved gases were studie d by ionization-threshold mass spectroscopy. Pyrolysis under isothermal con ditions reveals that the decomposition of poly(methylphenylsilane) is a typ e of depolymerization that has a first-order reaction. Kinetic analysis of the evolution spectra of CH3-Si-C6H5 radicals, phenyl and methyl substituen ts reveals the mechanism and activation energies of the decomposition react ions in main chains and substituents. It is found that the decomposition of main chains is a dominant reaction and results in the weight loss of appro ximately 90%. The effusion of phenyl and methyl substituents occurs in the two processes of rearrangement of main chains and the formation of stable S i-C containing residuals.