摘要： 以二苯基甲烷二异氰酸酯、聚酯二醇、二羟甲基丙酸等为原料合成了水性聚氨酯预聚体，用三乙胺中和制 备了水性聚氨酯的透明乳液。通过 FT-IR、TEM、拉力机等测试手段对所制水性聚氨酯进行了形貌观察、力学及耐水 性测试。结果表明，当 n(—NCO)∶n(—OH)比值为 1.8~1.9，DMPA含量在 6.5% ~7%，中和度在 10% ~120%时可 制得性能稳定的水性聚氨酯乳液，若在乳化阶段用乙二胺进行扩链，则胶膜的吸水率会进一步降低至 4%。

关键词: MDI, 水性聚氨酯, 吸水率, 断裂伸长率

Abstract: The aqueous polyurethane prepolymer was prepared through step-growth polymerization of di-phenylmethane disocyanate with polyester glycol and dimethylol propionic acid，which was then neutralized by triethylamine to form the stable transparent aqueous polyurethane dispersion.The morphology of the poly-urethane dispersion was measured by TEM and the mechanical properties and water resistance of the PU films were also tested as wel.From the results，it can be concluded that when n(—NCO)/n(—OH)was1.8~ 1.9 and DMPA content was 6.5% ~7%，the neutralization degre was 10% ~120%，the properties of the dispersion and mechanical properties of the film casted from the dispersion were the best.If ethylenedia- mine，a chain-extension agent，was aded into the dispersion in the proces of emulsification，the water absorptivity will be further decreased to 4%。

Key words: MDI, aqueous polyurethane, water absorptivity, elongation at break