Oxidative degradation of polydiene vulcanizates

Abstract

Intermittent and continuous stress relaxation measurements have been utilized to follow the oxidative degradation of vulcanizates of natural rubber, and of synthetically prepared polybutadienes. Vulcanizates were prepared by exposing samples to high-energy electrons. For natural rubber, only oxidative scission reactions were detected. Emulsion polymerized polybutadiene and all cis 1,4-polybutadiene exhibited both oxidative scission and oxidative crosslinking. With sulfur vulcanizates of these elastomers, there is superposed on the oxidation reactions a continued vulcanization caused by remaining curing agent.