The effects of chlorinated polyethylene(CPE) on the kinetic behaviors of suspension-swelling graft copolymerization of methyl mathacrylate(MMA)/styrene(S) in the synthesis of MCS resin were studied. The presence of CPE increases the viscosity of polymeric system and diffusion effect

makes the gel effect much earlier and decreases the maximum rate of copolymerization. CPE gives retardation and chain t'ransfer effects on the MMA/S copolymerization. The former will lower the rate

while the latter lower the molecular weight. In comparison with S

CPE will preferably adsorb MMA and swell with more MMA in a shorter time owing to their similar solubility parameters and specific interaction. It causes the different composition of MMA/S random and graft copolymers. The CPE con-tent

swelling time

conversion and the amount of mercaptan will affect the copo-lymer composition.