High-performance polyurethane materials are attracting more and more attention. In this work, a cooperative improvement of strength and toughness of rigid polyurethane (RPU) composites was achieved. 1.0 wt% long carbon fibers (LCFs) reinforced RPU composites were prepared and the effects of fiber oxidation treatment were studied. The results indicated that the surface roughness and wettability of LCFs were both increased, which could provide better physical bonding between LCFs and RPU matrix. Moreover, the increasing -OH groups on the fiber surface would react with RPU to form chemical bond. With the strengthened physical and chemical bonds, the interface of LCFs/RPU composites has been effectively improved. The mechanical properties showed that compared with pure RPU, the tensile strength, tensile modulus, bending strength, bending modulus, and impact strength of oxidized LCFs/RPU composites were increased by 171.1 %, 814.3 %, 29.1 %, 125.8 % and 110.1 %, respectively. Interlaminar shear strength (ILSS) was also increased by 65.1 %. Dynamic thermomechanical analysis (DMA) and scanning electron microscope (SEM) indicated the positive effects of the oxidation treatment on the interfacial bonding between LCFs and RPU matrix.

高性能聚氨酯材料越来越受到关注。在这项工作中，实现了硬质聚氨酯（RPU）复合材料强度和韧性的协同改善。制备了1.0 wt％长碳纤维增强的RPU复合材料，并研究了纤维氧化处理的效果。结果表明，LCFs的表面粗糙度和润湿性均增加，这可以在LCFs和RPU基质之间提供更好的物理结合。此外，纤维表面上增加的-OH基团将与RPU反应形成化学键。随着物理和化学键的增强，LCF / RPU复合材料的界面得到了有效改善。力学性能表明，与纯RPU相比，其抗拉强度，拉伸模量，弯曲强度，弯曲模量，氧化后的LCF / RPU复合材料的冲击强度分别提高了171.1％，814.3％，29.1％，125.8％和110.1％。层间剪切强度（ILSS）也增加了65.1％。动态热力学分析（DMA）和扫描电子显微镜（SEM）表明，氧化处理对LCF和RPU基体之间的界面结合具有积极作用。