The graft copolymerization of vinyl monomers onto polyvinyl alcohol (PVA) using Mn3+ ion complexed with pyrophosphate as initiator has been studied. It was found that manganic ion-PVA complex is an efficient redox initiator system for the graft copolymerization. The effect of the temperature

concentration of initiator and monomer (AN) on the reaction were investigated. Under the optimum condition the conversion of AN and the efficiency of graft will exceed 80% and 95% respectively and the graft percent of PAN in copolymer will reach 80% The initiation mechanism has been proposed tentatively.