超高分子量聚乙烯纤维的液相氧化改性及其环氧树脂基复合材料的力学和摩擦性能∗

摘要

为增强超高分子量聚乙烯(UHMWPE)纤维与环氧树脂(EP)基体之间的界面粘结强度,采用重铬酸钾溶液对 UHMWPE 纤维进行表面改性并制备 UHMWPE 纤维/EP 复合材料。结果表明,UHMWPE 纤维经液相氧化后表面刻蚀痕迹明显,表面粗糙度明显增加,结晶度增加了11.3%,与乙二醇的接触角减小了14.12°。与纯环氧树脂相比,纤维含量为0.4%的未改性 UHMWPE 纤维/EP 复合材料的拉伸强度降低18.04%,纤维含量为0.6%的液相氧化改性 UHMWPE 纤维/EP 复合材料的拉伸强度降低51.55%,未改性 UHMWPE(纤维含量0.5%)和液相氧化改性 UHMWPE(纤维含量0.4%)纤维/EP 复合材料的冲击强度分别提升了3.29%和4.39%。当纤维含量为0.3%时,液相氧化改性 UHMWPE 纤维/EP 复合材料的弯曲强度比纯环氧树脂增加6.55%,比未改性 UHMWPE纤维/EP 复合材料增加19%。当纤维含量由0增大到0.5%时,改性和未改性 UHMWPE 纤维/EP 复合材料的摩擦系数先增加后减小。%The effects of chromic acid liquid-phase oxidation treatment on ultra-high molecular weight polyethy-lene (UHMWPE)fibers were investigated to improve the interfacial adhesion between UHMWPE fibers and epoxy resin (EP).The UHMWPE fibers/EP composites were prepared with chromic acid-treated UHMWPE fibers.The results showed that the liquid-phase oxidation could effectively increase the fiber′s surface roughness,increase its crys-tallinity by 1 1.3% and reduce the contact angle with glycol by 14.12°.Compared with pure EP,the tensile strength of unmodified UHMWPE fibers/EP composite with a fiber content of 0.4wt% decreased by 18.04%,the tensile strength of liquid-phase oxidated UHMWPE fibers/EP composite with a fiber content of 0.6wt% decreased by 5 1.55%,the impact strength of unmodified UHMWPE (0.5wt% fiber content)and liquid-phase oxidated UHMWPE (0.4wt% fiber content)fibers/EP composite increased by 3.29% and 4.39%,respectively.Compared with the pure EP and unmodified UHMWPE fibers/EP composite,the flexural strength of liquid-phase oxidated UHMWPE fibers/EP composite increased by 6.55% and 1 9% respectively when fiber content was 0.3wt%.The friction coefficients of the unmodified and liquid-phase oxidated UHMWPE fibers/EP composite increased first and then decreased when the fiber content rose from 0 to 0.5wt%.