Continuous styrene - methyl methacrylate - Glycidyl methacrylate terpolymerizations in homogeneous mixtures with supercritical carbon dioxide

Free-radical terpolymerizations of styrene, methyl methacrylate, and glycidyl methacrylate were carried out in a tubular reactor in the presence of 20 wt.% CO2 at temperatures between 120 and 180degreesC and pressures of 300 and 350 bar. The number average molecular weights, M-N, were mostly between 2000 and 3000 g(.)mol(-1) and polydispersity indices around 2. In part of the experiments molecular weights were controlled by n-dodecyl mercaptan serving as the chain-transfer agent. PREDICI modeling indicates that the targeted molecular weights of M(N)similar to2500 g(.)mol(-1) and polydispersities around 2 may also be reached by using an initiator cocktail, a mixture of two initiators with significantly different decomposition rate coefficients. The predictions are confirmed experimentally.