Aqueous polymerization of acrylonitrile initiated by manganese(III) pyrophosphate-thiocyanate redox system: A kinetic study

The kinetics of aqueous polymerization of acrylonitrile monomer (M) initiated by the Mn-III-KNCS redox system have been studied under deaerated conditions in the temperature range 26-40 degrees C at constant ionic strength. The overall rates of polymerization and the disappearance of Mn-III were determined. The polymerization was initiated by the free radicals arising from the Mn-III-thiocyanate redox reaction. The rate of polymerization was investigated at various concentrations of monomer and initiator. The effects of varying [Mn-III], [NCS- ], pH, total [P2O74-], added [Mn-II] metal ions, ClO4-, Cl- and SO42- were examined. Dependence of the rate of polymerization on temperature was studied and activation parameters were computed from an Arrhenius plot. A suitable kinetic scheme consistent with the observed results is proposed and discussed.