A reverse ATRP process with a hexasubstituted ethane thermal iniferter diethyl 2,3-dicyano-2,3-di(p-tolyl)succinate as the initiator

Living/controlled radical polymerization of methyl methacrylate (MMA) was successfully carried out using the diethyl 2,3-dicyano-2,3-di(p-tolyl)succinate (DCDTS)/CuCl2/bipy initiation system, in which DCDTS is a hexasubstituted ethane thermal iniferter. The polymerization mechanism belongs to a new reverse atom transfer radical polymerization (ATRP) process with the initiator DCDTS reversibly decomposed to primary radicals in the initiation step. The molecular weights of the resulting PMMA increased with conversion, the molecular weight distributions of PMMA were quite narrow (MwMn < 1.30), and the first-order plots of ln([M](0)/[M]) versus time were linear. H-1 NMR analysis of PMMA revealed the presence of an alpha-(carbethoxy-cyano-tolyl)methyl end group from DCDTS fragments and an omega-chlorine group from catalyst. Since polymer is end-functionalized with a chlorine atom, it can then proceed the chain extension reaction with fresh MMA or the block copolymerization with the second monomer styrene (St) in the presence of CuCl/bipy catalyst.