Identification of the effect of ionizing radiation on epichlorohydrin-based homo-, co-, and ter-polymers

In this study, the effects of ionizing radiation on a series of epichlorohydrin (ECH)-based polymers, namely poly(epichlorohydrin) (CO) homopolymer, poly(epichlorohydrin-co-ethylene oxide) (ECO) copolymer, and poly(epichlorohydrin-co-ethylene oxide-co-allyl glycidyl ether) (GECO) terpolymer, were examined. Polymers are irradiated at room temperature with accelerated electrons in the 0–150 kGy absorbed dose range. The effect of irradiation on the chain structure polymers was examined with sol-gel and rheological analyses. While ECH-based homo- and co-polymers showed crosslinking up to a specific dose, it was found that chain scission above a critical dose value was more dominant. On the other hand, in the ECH terpolymer, crosslinking tendency in the 0–80 kGy dose range was found to be dominant over chain scission. It was found that radiation stability varies depending on the initial molecular mass of the copolymer. Using the Charlesby–Pinner and Charlesby–Rosiak equations for each polymer, the chain scission and crosslink yield ratio (p0/q0), gelation dose (Dg), and virtual gelation dose (Dv) were determined and the effect of ionizing radiation on these polymers, which has increased in use in recent years, was examined. In this study, the effect of ionizing radiation on the long-chain branching value of ECH-based polymers was also examined using a rubber process analyzer (RPA) and large amplitude oscillatory shear testing (LAOS), and a mechanism for the exchange of branching has been proposed.