The polymerization of vinyl monomers with N‐chlorosuccinimide in the presence of protic acids

The polymerization of vinyl monomers with N‐chlorosuccinimide (1) in the presence of protic acids such as p‐toluenesulfonic acid (PTS) was investigated. From the kinetic studies of the reaction of 1 with PTS and the polymerization of methyl methacrylate (MMA) with the above combined initiator system, it was found that the polymerization is initiated by a radical produced by a bimolecular reaction between 1 and PTS, and is terminated by a second order reaction. ESR investigations on the reaction mixture of 1 with PTS by spin trapping technique clearly showed that the initiating radical is the N‐succinimidyl radical. This radical results from a homolysis of the NCl bond of the protonated N‐chlorosuccinimide 2.