DEGRADATION OF POLY(METHYLPHENYLSILYLENE) AND POLY(DI-N-HEXYLSILYLENE)

Degradation of poly (methylphenylsilylene) and poly (di-n-hexylsilylene) was studied by chemical and mechanical methods at ambient and higher temperatures. Purely thermal degradation in solid state starts as a slow process at 150-degrees-C and provides soluble and insoluble products which include cyclosilanes as well as various siloxanes. Sonication at ambient temperatures leads to the mechanical degradation of high molecular weight polymers by homolytic cleavage induced by shear forces. No cyclics are formed under these conditions. Polysilanes in the presence of strong nucleophiles degrade exclusively to cyclic oligomers. Rate of this back-biting chain reaction depends on substituents at silicon atom, alkali metal, solvents, and temperature. Electrophiles degrade polysilanes to various alpha,omega-difunctional oligosilanes.