目的 研究水性聚氨酯（WPU）对聚乙烯醇（PVA）的增韧效果。方法 将固含量（质量分数）为35%的WPU按一定比例加入固含量为5%的PVA水溶液中，经混合、除泡、浇注、干燥后制成PVA/WPU共混膜。采用傅里叶红外光谱仪，扫描电子显微镜，差示扫描量热仪，动态热机械分析仪等对共混膜进行表征，并测试共混膜的力学性能、水接触角、吸水率。结果 随着WPU含量的增加，与纯PVA相比，共混膜的羟基（—OH）的伸缩振动峰向高波数方向移动，结晶度下降，玻璃化转变温度（tg）下降，拉伸强度降低，断裂伸长率增加，水接触角增大，吸水率降低，可见光透过率下降。结论 WPU的加入有利于提高PVA/WPU共混膜的韧性，在WPU质量分数为20%~30%时，得到了综合性能较佳的共混膜。

This work aims to study the toughening effect of waterborne polyurethane (WPU) on polyvinyl alcohol (PVA). The PVA/WPU blend membrane was prepared by adding WPU with a solid content (mass fraction) of 35% into the PVA aqueous solution with a solid content of 5% and mixing, defoaming, pouring and drying. FTIR, SEM, DSC and DMA were used to characterize the blend membrane, and the mechanical properties, water contact angle and water absorption of the blend membrane were tested. The result showed that with the increase of WPU content, compared with pure PVA, the stretching vibration peak of hydroxyl (—OH) of the blend membrane moved to the direction of high wave number; the crystallinity decreased; the tg decreased; the tensile strength decreased; the elongation at break increased; the water contact angle increased; the water absorption decreased; and the visible light transmittance decreased. It is concluded that the addition of WPU can improve the toughness of PVA/WPU blend membrane. When the mass fraction of WPU is 20%-30%, the blend membrane with better comprehensive properties can be obtained.