Mechanistic studies of thiol-dimethylsulfoxide initiated polymerization of methylmethacrylate from endgroup analysis

Abstract

Endgroup analysis of polymethylmethacrylate obtained by initiation with thiol-dimethyl sulfoxide systems has been carried out using dye-techniques developed in our laboratory. Thiols used are 2-mercaptoethylamine hydrochloride, 2-mercaptoethanol, thioglycolic acid and n-butane thiol. The first three thiols incorporated amine, hydroxyl and carboxyl endgroup respectively to the extent of about one per macromolecule, while the last one as expected produced none of the above functional endgroups in the polymer. In the light of endgroup results initiation through thiyl radicals has been suggested. Probable termination mechanism has also been discussed.