BLOCK COPOLYMERIZATION INITIATED BY MN(III)-POLY(ETHYLENE GLYCOL) REDOX SYSTEM - GENERAL FEATURES AND KINETICS

The kinetics and mechanism of thermal polymerization of acrylonitrile initiated by Mn(III) pyrophosphate - poly(ethylene glycol) (PEG, molecular weight 6000) redox system in aqueous sulfuric acid medium was studied in the temperature range 30-60-degrees-C. The overall rates of polymerization and the disappearance of Mn3+ were determined. The polymerization was initiated by the organic free radical produced from the Mn3+-PEG reaction and the termination was by the metal ions. The rate of polymerization of acrylonitrile was found to be directly proportional to the square of the monomer concentration and first power of PEG concentration, and inversely proportional to the concentration of Mn3+. The rate of manganic ion disappearance was found to be directly proportional to manganic ion concentration and PEG concentration, and independent of the monomer concentration. Based on these observations, a plausible reaction scheme was suggested and suitable kinetic expressions were evaluated.