Graft copolymerization of 2-vinyl pyridine and styrene onto isotactic polypropylene powder by the preirradiation method

Preirradiated isotactic polypropylene (IPP) powder has been modified by gra fting 2-vinyl pyridine (2-VP) and styrene (Sty) in an aqueous medium. The g raft copolymerization reaction was studied under different experimental con ditions such as total dose, monomer concentration, amount of the solvent, t ime of reaction and temperature to determine the optimum conditions for aff ording maximum percentage of grafting (P-g). Maximum grafting percent of 2- VP (180%) and styrene (117%) was obtained under optimum conditions. The rat e of grafting (R-g) of 2-VP and styrene has also been determined as a funct ion of total dose, initial monomer concentration and the reaction temperatu re. From maximum P-g and different R-g values of 2-VP and Sty, 2-VP is more reactive towards grafting as compared to styrene under optimum conditions. Characterization of the graft copolymers is based on differential scanning calorimetric (DSC) analysis. Isolation of the grafted poly(2-VP) and poly( styrene) chains from the grafted samples provides an additional evidence of formation of the graft copolymer. (C) 1999 Elsevier Science S.A. All right s reserved.