Polymerization of methyl methacrylate by 2-pyrrolidinone and n-dodecyl mercaptan

The bulk polymerization of methyl methacrylate initiated with 2-pyrrolidinone and n-dodecyl mercaptan (R-SH) has been explored. This polymerization system showed "living" characteristics; for example, the molecular weight of the resulting polymers increased with reaction time by gel permeation chromatographic analysis. Also, the polymer was characterized by Fourier transform infrared spectroscopy, ¹H NMR, and ¹³C NMR techniques. The polymer end with the iniferter structures was found. By the initial-rate method, the polymerization rate depended on [2-pyrrolidinone]^1.0 and [R-SH]⁰. Combining the structure analysis and the polymerization-rate expression, a possible mechanism was proposed. n-Dodecyl mercaptan served dual roles - as a catalyst at low conversion and as a chain-transfer agent at high conversion. Finally, the thermal properties were studied, and the glass-transition temperature and thermal-degradation temperature were, respectively, 25 and 80-100°C higher than that of the azobisisobutyronitrile system.