Abstract: The microstructure, responding degree and main properties of unsaturated polyester modified with polyurethane were studied with SEM, FT-IR, contact angle and mechanical properties testing.The study showed that with the addition of polyurethane, the toughness of unsaturated polyester was improved, the interface soaking with natural fiber was increased and the curing shrinkage rate was lowered.The impact fracture section of modified unsaturated polyester showed ductile failure.The interface soaking with natural fiber was increased when the contact angle was lowered with the increase of polyurethane content.The testing of mechanical properties showed that when the content of PU was 5%, the impact strength was increased by 80%, the decrease of flexural modulus was less than 20% and the curing shrinkage rate was less than 4%.

摘要： 利用与天然纤维具有良好亲和性的聚酯聚氨酯(PU)改性不饱和聚酯(UP)，通过扫描电镜（SEM）、傅里叶红外光谱（FT-IR）、接触角和力学性能等，研究了改性不饱和聚酯的微观结构、反应程度和主要性能.研究结果表明，引入PU提高了不饱和聚酯树脂的韧性，增加了与天然纤维的界面浸润性，降低了不饱和聚酯树脂的固化收缩率.所得改性不饱和聚酯的冲击断裂截面表现为韧性断裂;与天然纤维的接触角随着聚氨酯添加量的增加而降低，表明改性不饱和聚酯与天然纤维的浸润性增强.力学性能测试表明，当PU含量为5%时，其冲击强度可提高80%，弯曲模量降低小于20%，固化收缩率低于4%.