目的 采用六亚甲基二异氰酸酯（HDI）、聚碳酸酯二元醇（PCDL）和己二醇（HDO）合成一种新型聚氨酯，研究R值（在整个预聚反应中异氰酸酯与羟基的摩尔比）对聚氨酯薄膜（PU膜）性能的影响。方法 采用预聚法将不同R值的原料进行化学合成，然后流延成膜。分析R值对PU膜力学性能、水接触角、透明度和氧气透过性的影响，并通过红外光谱、差示量热扫描分析和热重分析对PU膜进行测试表征。结果 随着R值的增加，PU膜的力学性能和热稳定性变好，水接触角和微相分离程度增大，透明度和氧气透过系数降低。结论 使用以上3种原料合成了一种新型聚氨酯，且随着R值的增加，PU膜的综合性能得到提升。

The work aims to synthesize a new polyurethane with hexamethylene diisocyanate (HDI), polycarbonate diol (PCDL) and hexanediol (HDO) to study the effects of R value (molar ratio of isocyanate to hydroxyl group in the whole prepolymerization reaction) on the performance of polyurethane film (PU film). Raw materials with different R values were chemically synthesized by prepolymerization and then cast into a film. The effects of R value on mechanical properties, water contact angle, transparency and oxygen permeability of PU film were analyzed. The PU film was tested and characterized by infrared spectroscopy, differential scanning calorimetry and thermogravimetric analysis. As the R value increased, the mechanical properties and thermal stability of the PU film became better, the water contact angle and microphase separation degree increased, but the transparency and oxygen permeability coefficient decreased. A new type of polyurethane is synthesized with the above-mentioned three raw materials, and the overall performance of the PU film is improved as the R value is increased.