NEW PERACID-TYPE POLYMERIC INITIATOR FOR RADICAL POLYMERIZATION

In this study, a radiation-induced copolymer, namely polyethylene-g-acrylic acid powder, was used, whose carboxyl groups can be oxidized to form a highly reactive polymer initiator. The activation energy for its decomposition is 22.4 kcal/mol. It was found that the peracid-type polymeric powder was effective as an initiator for radical polymerization. It had high reactivity toward 2-hydroxyethyl methacrylate (HEMA), which could be easily grafted onto the polymeric powder; also, the homopolymer could be obtained. The kinetic investigation indicated that this polymerization proceeded by a radial mechanism, and the overall activation energy of homopolymerization was 18.67 kcal/mol and the overall activation energy of bigraft polymerization was 17.35 kcal/mol. By using the peracid-type polymeric powder as initiator for the copolymerization of methyl methacrylate with styrene, it was confirmed that the polymerization initiated by the peracid-type polymeric powder was a radical reaction.