Effect of chlorination on the radiation protection of polyethylene and poly(1,4-cis-isoprene) rubber

In order to find the change in the chemical structure of the polymer and the role of chlorine atom in the polymer for radiation stability, the radiation-induced gas evolution of chlorinated polyethylene, chlorinated and hydrochlorinated poly(1,4-cis-isoprene) was measured. The chlorination of polyethylene brought about an increase in the radiation stability. While the stability decreased over 30% of chlorine substitutions. The chlorination and hydrochlorination of poly(1,4-cis-isoprene) reduced monotonously the radiation stability. With the chlorinated and hydrochlorinated poly(1,4-cis-isoprene) at the same chlorine substitution, the former gave lower gas evolution than the latter. This rubber hydrochloride showed relatively low gas evolution by the self absorption of evolved gas, but was found to be relatively unstable against radiation. (author)