Abstract: ACS resin is a type of grafting copolymer, in which styrene (St) and acrylonitrile (AN) as co-monomers were grafted onto the molecular chain of chlorinated polyethylene (CPE). The effect of swelling conditions of CPE rubber on the grafting rate, Izod impact strength and phase morphology of the ACS resin synthesized in this work through bulk polymerization were synthesized by bulk polymerization, and the molecular weight and molecular weight distribution of free SAN in the ACS resin were also investigated. The results indicated that the swelling temperature and time of CPE rubber significantly influenced the grafting rate, Izod impact strength and phase morphology of ACS resin and the molecular weight of free SAN in the ACS resin. However, there was no effect on the molecular weight distribution of free SAN. The optimum grafting rate, phase morphology, Izod impact strength of ACS resin and the optimum molecular weight of free SAN could be achieved for the synthesized resin only when CPE rubber swelled fully. The CPE rubber could swell quickly and fully at 100 ℃ within 3 h. The resin could gain an optimum grafting rate of 23.1 %, Izod impact strength and phase morphology under the above condition.

Key words: chlorinated polyethylene, swelling condition; grafting rate; free; molecular weight; im-pact propertymicroscopic morphology