【作者】 贺俊卿；

【导师】 李春忠；

【作者基本信息】 华东理工大学 ， 材料科学与工程， 2011， 博士

【摘要】 现代机械、电子、医疗设备等领域的飞速发展,使得各类滑动部件,如：轴承、导轨、滑板、活塞环等的应用越来越广泛。随着高科技的不断进步,精密仪器、电子电器及各种产业机械不断向小型化、轻型化、高性能、高速化发展,动力传动传导的条件变得越来越苛刻。导热型自润滑聚合物基复合材料是研究的重点方向之一,其开发和应用具有重要意义。本文以微米铜粒子作为导热填料,采用聚四氟乙烯(PTFE)以及紫外光辐照接枝法制备的聚乙烯(LLDPE/HDPE)接枝全氟烷基乙基甲基丙烯酸酯(PFAMAE)作为固体润滑剂,通过双螺杆挤出的方法制备出可用于轴承或齿轮的导热型自润滑聚甲醛复合材料,研究了铜粒子及固体润滑剂对聚甲醛(POM)导热性能及摩擦磨损性能的影响。1.采用双螺杆挤出的方法制备了金属铜粉改性的POM导热复合材料,研究了铜粒子对复合材料热导率及摩擦磨损性能的影响。实验结果表明：当铜含量大于7.3vo1%时,复合材料的热导率随着铜含量的增加而增加。铜粒子的引入不仅提高了复合材料的热导率,而且降低了材料的摩擦系数,但导致磨损率增大。2.采用PTFE作为固体润滑剂制备了POM/Cu/PTFE复合材料,研究了PTFE对材料导热性及摩擦磨损性能的影响,并对材料的导热模型及磨损机理进行了探讨。经过PTFE改性后,复合材料的热导率与POM/Cu体系相比基本不变,摩擦系数和磨损率降低。POM/Cu/PTFE复合材料的磨损主要为粘着磨损和磨料磨损。3.采用紫外光辐照接枝的方法成功将PFAMAE接枝到聚乙烯(LLDPE/HDPE)分子链上,开发出新型固体润滑剂PE-g-PFAMAE,研究了其对复合材料摩擦磨损性能的影响。实验结果表明：PE-g-PFAMAE的添加改善了PE分散相在POM基体中的分散性,效果优于传统PE相容剂PE-g-MAH; PE-g-PFAMAE可以有效地提高复合材料的摩擦磨损性能,在摩擦过程中形成均匀的润滑层,降低了材料的磨损。复合材料的磨损机理主要为粘着磨损与磨料磨损。4.将实验室自制的新型固体润滑剂HDPE-g-PFAMAE加入POM/Cu复合材料,研究了HDPE-g-PFAMAE对复合材料导热性及摩擦磨损性能的影响,并与传统固体润滑剂PTFE做了对比。实验结果表明：HDPE-g-PFAMAE改性的POM复合材料中,填料粒子在基体中的分散性较好,呈球状颗粒分布,粒子间距离缩短,更易形成导热通路；HDPE-g-PFAMAE的加入在降低材料摩擦系数与磨损率的同时,还进一步提高了材料的热导率；HDPE-g-PFAMAE对POM复合材料的减摩效果与PTFE相当,耐磨性及力学性能均优于PTFE; HDPE-g-PFAMAE减少了材料的磨料磨损,复合材料的磨损过程主要为粘着磨损。更多还原

【Abstract】 The various sliding parts, such as bearing, lead rail, slide plate and piston ring, have a wider application owing to the rapid development of modern machine, electronic industry and armamentarium. With the continuous improvement of high technology, the precision instruments, electronic and electrical products and all kinds of industry machines have developed to be smaller, lighter, high-performance and faster. The conditions of power transmission have been more and more severe. Therefore, the development and application of self-lubricating materials with improved thermal conductivity is of great importance. In this paper, the self-lubricating POM composites with improved thermal conductivity were prepared by incorporation of copper powder and solid lubricants via extruding method. The solid lubricants were PTFE and PFAMAE grafted polyethylene which was prepared by UV-induced surface graft polymerization. The effect of copper and solid lubricants on thermal conductivity and tribological properties of POM composites were studied.1. The thermally conductive POM/Cu composites were prepared by extruding. The effect of copper particles on thermal conductivity and tribological properties of POM composites were studied. The results indicated that the thermal conductivity of composites was increased with the copper content increasing when copper content was above 7.3vol%. The addition of copper particles not only improved the thermal conductivity but also reduced the friction coefficient of composites. However, the wear rate was increased.2. POM/Cu composites were modified by solid lubricant PTFE. The effect of PTFE on the thermal conductivity and tribological properties of materials were studied. The thermal conductivity model and wear mechanism were discussed. The incorporation of PTFE has little effect on the thermal conductivity of composites compared with that of POM/Cu, but reduced the friction coefficient and wear rate. The wear mechanism of POM/Cu/PTFE composites was adhesive wear and abrasion wear.3. The new solid lubricant was successfully developed by grafting PFAMAE onto polyethylene chains via UV-induced surface graft polymerization. The effect of this lubricant on the tribological properties of POM composites was studied. The results indicated that the incorporation of PE-g-PFAMAE improved the compatibility between POM and PE and tribological properties of composites. The uniform lubricating layer was formed during sliding which reduced the wear of materials. The wear mechanism of PE-g-PFAMAE lubricated composites was adhesive wear and abrasion wear.4. The POM/Cu composites lubricated by HDPE-g-PFAMAE were prepared. The effect of HDPE-g-PFAMAE on the thermal conductivity and tribological properties of composites was studied, which was also compared with that of PTFE. The results indicated that the dispersion of fillers in HDPE-g-PFAMAE lubricated composites was better. The distance among the particles decreased which was helpful for the formation of conductive pathways. The addition of HDPE-g-PFAMAE not only reduced the friction coefficient and wear rate of composites but also improved the thermal conductivity. The effect of HDPE-g-PFAMAE on lowering the friction of materials was similar to that of PTFE, but better than PTFE on improving the wear resistance and mechanical properties. The addition of HDPE-g-PFAMAE reduced abrasion wear of materials. The wear mechanism was mainly adhesive wear.更多还原