Pulsed laser polymerization of cyclohexyl acrylate involving fragmentation of mid-chain radical

Pulsed laser polymerization (PLP) of cyclohexyl acrylate (CHA) was carried out to optimize the PLP conditions for determination of consistent propagation rate coefficients (kps). Concurrence of mid-chain radicals (MCRs) formed primarily by backbiting and propagating radicals as an unavoidable feature of acrylate polymerization for kinetic study was confirmed by ESR spectroscopy. The molecular weight distributions (MWDs) of the resultant polymers measured by GPC were carefully inspected to exclude the influence of the low reactivity and beta-fragmentation of MCR in order to obtain consistent values of k(p). The PLPs at the low initiator concentrations where the influence of MCR could be minimized were found to give MWDs suitable for k(p) determination. The k(p) values obtained for CHA were comparable with reported values for other acrylic esters.