Polymerization of acrylonitrile initiated by $KO_2$-nitrobenzene

Abstract

Polymerization of acrylonitrile initiated by $KO_2$- Nitrobenzene system was carried out in anhydrous DMSO at 25$^\circ$C. Initial rate of polymerization was very rapid and the high molecular weight was obtained. The molecular weight was proportional to monomer concentration and inversely to concentration of initiator within 15 minutes. The anion radicals which were produced by the reaction of $KO_2$ with charge transfer agents such as nitrobenzene, benzoquinone, benzophenone and naphthalene, were effective for the polymerization of acrylonitrile. The overall activation energy was estimated to be -2.6 Kcal/mol in the temperature range of 20 to 50$^\circ$C. It is proposed that polymerization proceeds via anionic mechanism involving one-electron transfer from nitrobenzene anion radical to monomer.