A STUDY OF THE LIVING FREE-RADICAL POLYMERIZATION USING DIFFERENTIAL SCANNING CALORIMETRY

The living radical polymerization of styrene, some styrene-analogous v inyl monomers as well as methyl methacrylate (MMA) and butyl methacryl ate (BuMA) was investigated with a differential scanning calorimeter. The ability to polymerize was estimated by dynamic measurements, showi ng that p-methylstyrene, p-chlorostyrene, 3,4-dimethoxystyrene and 4-v inylpyridine polymerize in the presence of 2,2,6,6-tetramethyl-1-piper idine-N-oxyl (TEMPO) while MMA and BuMA do not. Isothermal measurement s revealed an activation energy of E-A = 81 kJ mol(-1) for thermal bul k polymerization of styrene and values of E-A = 78-94 kJ mol(-1) were measured with different iniferter systems. These polymerizations have induction times which depend on the reaction temperature and the initi al concentration of the iniferter systems. An influence of the kind of nitroxyl radical on the induction times was not observed.