Gelatin-methyl methacrylate graft copolymers were prepared with gelatin and methyl methacrylate (MMA). The effect of various reaction parameters on the swelling behavior was investigated systematically, such as the concentration of the monomer, the content of the initiator, reaction time and temperature. In addition, the effect of intercalation of graft copolymers with montmorillonite (MMT) on swelling behavior was studied. The results indicated that the graft copolymerization and intercalation with MMT could greatly reduce the swelling degree of gelatin. The swelling process of the copolymers followed second-order kinetics identical to that of the original gelatin. (c) 2005 Springer Science + Business Media, Inc.