Effect of aromatic protectors on the radiolysis of polyorganosiloxanes

Abstract

The influence of phenyl and other aromatic groups on radiation crosslinking of polydimethylsiloxane and its mechanical blends and copolymers with polydiphenylsiloxane and polyphenylsilsesquioxane, radiation-induced gas evolution, and radical generation in these systems were considered. It was shown that radiation-chemical yields of crosslinking and gas evolution follow a simple exponential law over a wide concentration range of phenyl groups (at their content above 1 mol %). A similar dependence was observed for the radiation-chemical yield of hydrogen in ethylene copolymers with styrene. For the crosslinking processes, it was proved that the effect of phenyl groups is identical in the mechanical blends and copolymers of polyorganosiloxanes. The effect of retardation of radiation-chemical processes by phenyl groups was shown to be independent of whether one or two groups is linked to a silicon atom, it is their total amount that matters.