EFFECT OF IONIZING-RADIATION ON POLYSILANE

ESR and gel permeation chromatographic measurements of poly(diethylsil ane) and poly(cyclohexylmethylsilane) gamma-irradiated at temperatures between 77 K and 300 K were carried out to elucidate the mechanism of radiation-induced degradation of polysilanes. Radical species observe d after the irradiation are not silyl-type radicals generated by the c leavage of the Si-Si bond but alkyl radicals generated by the scission of the C-H bond. The G value of the main-chain scission depends stron gly on the irradiation temperature and dose. It is proposed that sigma -conjugation along the main chain allows the migration of the radiatio n energy to the weakest bond in the main chain where the direct scissi on of the bond is induced.