【目的】为改善水性聚氨酯耐水性、热稳定性及与聚乳酸（PLA）基材附着力不足的缺陷，拓展其在包装印刷领域的应用潜力。【方法】以聚乳酸二元醇（PLA-1000/PLA-2000）和聚二甲基硅氧烷（PDMS-1000）为复合软段，结合双功能扩链剂（DDA）与封端剂（HBT）制备了 PLA/聚硅氧烷复合型自交联水性聚氨酯分散体（PWPU）。系统研究了 PDMS与 PLA配比对材料性能的影，响。采用红外光谱仪、热重分析仪及差示扫描量热仪表征了材料结构与热性能，测试了涂层接触角、表面张力、吸水率及拉伸性能，系统分析了其表面耐水性与力学性能。【结果】PDMS的引入显著改善了材料柔韧性，PWPU-2断裂伸长率达 234. 86%，较纯 PLA基 PWPU-1提升 99%；同时，PDMS疏水链段向膜表面富集，形成低表面能疏水层，使 PWPU-3（PLA/PDMS复配）吸水率降至 4. 54%，水接触角达 74. 32°。热稳定性分析显示引入 PDMS后材料的初始热分解温度略有下降，这是 PDMS含量与 PLA软段分布共同作用的结果，但硬段主导的主分解温度未受影响。界面性能方面，PWPU-3在电晕处理 PLA膜上界面张力仅 0. 489 mN/m，黏附能达 69. 48 mJ/m²，且铺展系数>0，表明其具备优异的附着性和内聚失效特性。【结论】制备的复合型水性聚氨酯兼具高柔韧性、低吸水率、良好热稳定性及对 PLA薄膜的强附着力，有望作为 PLA包装印刷的环保型油墨连接料。

［Objective］To address the shortcomings of poor water resistance，thermal stability， and insufficient adhesion to PLA substrate in waterborne polyurethane，and to expand its application potential in the packaging and printing industry.［Methods］ A PLA/polysiloxane composite self-crosslinking waterborne polyurethane dispersion（PWPU）was prepared using polylactic acid diol（PLA-1000/PLA-2000）and polydimethylsiloxane（PDMS-1000）as composite soft segments，combined with a bifunctional chain extender（DDA）and a chain terminator（HBT）. The influence of the PDMS-to-PLA ratio on the material properties was systematically studied. The material structure and thermalproperties were characterized by infrared spectroscopy（FT-IR）thermogravimetric analysis（TG），and differential scanning calorimetry（DSC）. The water contact angle，s，urface tension，water absorption rate， and tensile properties were tested，and the surface，water resistance，and mechanical properties were systematically analyzed.［Results］The introduction of PDMS significantly improved the flexibility ofthe material. The elongation at break of PWPU-2 reached 234. 86%，which was 99% higher than that of pure PLA-based PWPU-1. Meanwhile，the hydrophobic segments of PDMS were enriched on the membrane surface，forming a low surface energy hydrophobic layer，which reduced the water absorption rate of PWPU-3（PLA/PDMS blend） to 4. 54% and increase the water contact angle to 74. 32° .Thermal stability analysis showed that the initial thermal decomposition temperature of the materialslightly decreased after the introduction of PDMS. This was the result of the combined effect of PDMScontent and the molecular weight distribution of the PLA soft segment，but the main decompositiontemperature dominated by hard segments was not affected. In terms of interfacial performance，the interfacial tension of PWPU-3 on the PLA film treated with corona was only 0. 489 mN/m，the adhesion energy reached 69. 48 mJ/m2，and the spreading coefficient was greater than zero，indicating excellent adhesion and cohesive failure characteristics.［Conclusion］ The prepared composite waterborne polyurethane exhibit high flexibility，low water absorption，good thermal stability and strong adhesion to PLA films，making it a promising eco-friendly binder for PLA packaging inks.