Kinetic Analysis on Pyrolysis of Poly(methylphenylsilane)

Abstract

Pyrolysis of poly(methylphenylsilane) in the states of powder, film, and photooxidized film has been studied by mass spectroscopy. The kinetic analysis of the evolution spectra of a unit of the polysilane CH3−Si−C6H5 and one of substituents C6H5 gives the mechanism and activation energies of decomposition reactions. The thermal decomposition of poly(methylphenylsilane) is a type of depolymerization with random initiation. It is found that the activation energies of thermal decomposition have Gaussian distributions rather than keeping constant values. The activation energies of thermal decomposition in film are higher than that in powder because of its stronger interaction among the molecules. Due to the photodegradation and photoinduced oxidation of polysilane, photooxidized film has higher activation energies of decomposition and a broader distribution of activation energies than the unoxidized film.