剑麻纤维和低密度聚乙烯填充聚甲醛复合材料的摩擦磨损性能

摘要

通过双螺杆挤出熔融共混的方法制备剑麻纤维(SF)和低密度聚乙烯(LDPE)共同填充的聚甲醛复合材料,在HT-500型高温摩擦磨损试验机上考察其干滑动摩擦条件下的摩擦磨损性能,并通过扫描电子显微镜(SEM)观察其磨损表面形貌,分析磨损机制.结果表明:添加适量的LDPE能显著降低POM的摩擦因数和磨损率,当LDPE质量分数为5%时,复合材料的摩擦因数下降21.7%,磨损率降低10%;随SF质量分数的增加,POM/5%LDPE/SF复合材料的摩擦因数和磨损率呈现先增大后减小再增大的趋势,当SF质量分数为5%时,复合材料摩擦磨损性能优异,在转速为1 120 r/min,恒定载荷为8 N的实验条件下,其稳定摩擦因数为0.16,磨损率为1.61×10-6 mm3/ (N·m).纯POM磨损方式以黏着磨损为主,POM/5%LDPE/SF复合材料以疲劳磨损为主,伴随有转移膜的剥落.%Polyoxymethylene ( POM ) composites filled with low-density polyethylene (LDPE) and sisal fibers (SF) were prepared by melt blending on the twin-screw extruder.Under dry sliding condition, the friction and wear performances were tested by HT-500 high-temperature friction and wear tester.The worn surfaces of the composites were observed and the major wear mechanism was analyzed by scanning electron microscopy (SEM).The results show the friction coefficient and wear rate of POM composites could be reduced by adding proper LDPE, and respectively decreasing by 21.7％, 10％ when the content of LDPE is 5％.With the increase of SF content, the friction coefficient and wear rate of POM / 5％ LDPE/SF composites show a tendency of first increasing, then decreasing and then increasing again.Under the experimental condition of speed for 1 120 r/min and constant load for 8 N,the composite containing 5％ SF has an excellent friction and wear properties,and its friction coefficient is 0.16 and wear rate is 1.61 × l0-6mm3/ (N ·m).The main wear mechanism of pure POM is adhesive wear and POM/5％ LDPE/SF composite is fatigue wear and spalling of the transfer film.