Thermal decomposition of poly(methylphenylsilane)

The thermal decomposition of poly(methylphenylsilane) was performed at constant heating rates and isothermal conditions. The evolved gases were studied by ionization-threshold mass spectroscopy. Pyrolysis under isothermal conditions reveals that the decomposition of poly(methylphenylsilane) is a type of depolymerization that has a first-order reaction. Kinetic analysis of the evolution spectra of CH3-Si-C6H5 radicals, phenyl and methyl substituents reveals the mechanism and activation energies of the decomposition reactions 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 approximately 90%. The effusion of phenyl and methyl substituents occurs in the two processes of rearrangement of main chains and the formation of stable Si-C containing residuals.