反应详情

Zhong et al, U.S. Pat. No. 5,663,258, discloses strongly-swellable, moderately-crosslinked copolymers of vinylpyrrolidone and vinyl acetate (PVP/VA). The PVP/VA copolymer of the Zhong reference is formed by coprecipitation in an organic solvent, such as cyclohexane or heptane, in the presence of a free radical initiator and a crosslinker material, such as N,N′-divinylimidazolidone, 1-vinyl-3(E)-ethylidene pyrolidone, pentaerythritol triallyl ether, triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione and 2,4,6-triallyloxy-1,3,5-triazine. The resulting PVP/VA copolymer is water insoluble.