A series of poly(vinyl acetate-co-acrylamide)copolymers with different mole ratios of vinyl acetate to acrylamide units were synthesized by emulsion polymerization for investigating the influences of copolymer composition upon the performance such as apparent viscosity,film behaviors,and adhesion capacity to fibers for warp sizing operation.The mole ratios of vinyl acetate to acrylamide were varied from 0 to 4.By using an impregnated roving method,the adhesion was evaluated in terms of the maximal strength and work to break of a slightly sized roving.The film behaviors included breaking strength,breaking elongation,solution time and hygroscopic capacity.It was found that the viscosity,adhesion capability,glass transition temperature and film behaviors of the copolymeric sizing agent strongly depended on the mole ratio.Excessively increasing the amounts of vinyl acetate or acrylamide units incorporated into the copolymeric chains damages much of the performance.A favorable mole ratio of vinyl acetate or acrylamide was found to be 45∶55.Based on this mole ratio,the adhesion capability and film behaviors of the sizing agent reach their maximal values simultaneously.This demonstrates that the sizing agent should be synthesized under this copolymer composition from the viewpoint of adhesion and film behaviors. A series of poly (vinyl acetate-co-acrylamide) copolymers with different mole ratios of vinyl acetate to acrylamide units were synthesized by emulsion polymerization for investigating the influences of copolymer composition on the performance such as apparent viscosity, film behaviors, and adhesion capacity to fibers for warp sizing operation. The mole ratios of vinyl acetate to acrylamide were varied from 0 to 4.By using an impregnated roving method, the adhesion was evaluated in terms of the maximal strength and work to break of a slightly sized roving.The film behaviors included breaking strength, breaking elongation, solution time and hygroscopic capacity. It was found that the viscosity, adhesion capability, glass transition temperature and film behaviors of the copolymeric sizing agent strongly depended on the mole ratio. Excessively increasing the amounts of vinyl acetate or acrylamide units incorporated into the copolymeric chains damages much of the performance. A favorable mole ratio of vinyl acetate or acrylamide was found to be 45:55. Based on this mole ratio, the adhesion capability and film behaviors of the sizing agent reach their maximal values ​​when. This demonstrates that the sizing agent should be synthesized under this copolymer composition from a viewpoint of adhesion and film behaviors.