环保型水性聚氨酯的改性研究

Modification of Environmental Friendly Waterborne Polyurethane

先通过本体聚合和溶液聚合,合成聚氨酯预聚体;在中和阶段,加入乙烯基共聚单体降低体系粘度,合成羟甲基丙烯酰胺封端的聚氨酯乳液;然后在此基础上通过甲基丙烯酸甲酯(MMA)单体的乳液共聚,制备了具有核壳结构的聚氨酯-聚甲基丙烯酸甲酯复合乳液。采用红外光谱对制备的复合乳液进行表征,用凝胶色谱法测定其数均和重均相对分子质量。乳液及其涂膜性能测试结果表明,随着MMA用量增加,改性聚氨酯乳液的粘度降低,但涂膜的吸水率降低、拉伸强度增大。

Polyurethane- polymethylmethacrylate composite emulsion （PUA） with core -shell structure was prepared by the copolymerization of methyl methaerylate（MMA） in the presence of N- hydroxymethyl acrylamide polyurethane dispersions as seeded emulsion, which was obtained by adding vinyl monomer during the course of the prepolymer polyurethane neutralization in order to reduce the viscosity of the system. The PU and the PUA were characterized by IR, and M. and Mw of the PU and PUA were test by GPC. The test results of the properties of the emulsion and its coating film showed that the viscosity of the modified PUA emulsion decreased, but the water absorption rate of its coating film decreased and the tensile strength of its coating film increased with increasing amount of MMA.