The copolymerization of polystyrene macromers with vinyl acetate was studied. The results show that the grafting efficiency increases with amount of initiator

polymerization temperature and charging ratio of vinyl acetate to the macromer

and decreases with increasing average molecular weight of the macromers. There exists a maximum value in the relationship between the grafting efficiency and the total monomers concentration. During copolymerization the conversion rate of the polystyrene macromer is faster than that of vinyl acetate at the beginning while slower at the later stage. The graft copolymers were purified by extractions and charac-terized by GPC

IR

1H-NMR

PGC and TEM.The last indicates a microphase separation in the graft copolymer.