Radiation-induced chemical processes in polyorganosiloxanes

Radiation-induced changes in polymethylphenylsilsesquioxane block copolymers at γ radiation doses 10-100 kGy, dose rates 0.01 MGy/h, were studied by UV spectroscopy and electrophoresis. It was found that a pregel was formed at doses of 30-50 kGy and gel formation mainly occurred in polydimethylsiloxane (PDMS) blocks. The UV spectrophotometry of samples in a cyclohexane solution demonstrated that, at doses of 10-50 kGy, a noticeable broadening of absorption bands due to phenyl groups was observed only in oligophenylsilsesquioxane and not in the block copolymers. Hydrogen atoms formed in the radiolysis of PDMS did not reach polyphenylsilsesquioxane blocks