A grafting water-swellable elastomer (WSE) that is, chlorinated polyethylene (CPE)-graft-poly(ethylene glycol) (PEG), was synthesized by a grafting reaction. The synthesis was based on the reaction between chlorine in CPE and sodium salt of PEG. PEG with molecular weights of 600 and 1000 were used. The maximum grafting percentage of the resulted copolymers after purification was 9.79%. The structure of the copolymer was confirmed by an IR spectrum. The grafting degree and PEG content increased with increasing reaction time and reaction temperature. The equilibrium swelling degree of the grafting copolymer was very small, only 16.94%. However, for the crosslinking WSE, the swelling degree was influenced by the absorbency temperature and absorbency time. The absorbency rate was faster than that of the grafting WSE, and the swelling degree in the equilibrium state was higher than that of the grafting WSE, too. The maximum swelling degree of the crosslinking WSE was 70%. (c) 2007 Wiley Periodicals, Inc.