碳纤维-碳纳米管多尺度增强聚四氟乙烯复合材料摩擦学性能研究

Tribological performance study of carbon fibre-carbon nanotube multiscale reinforced polytetrafluoroethylene composites

  • 摘要: 针对传统化学法易损伤纤维、污染严重的缺点,采用稀土LaCl3表面处理方法合成碳纤维(Carbon Fibre, CF)-碳纳米管(Carbon Nanotube, CNT)微纳多尺度增强体,通过烧结工艺制备CF-CNT多尺度增强聚四氟乙烯(Polytetrafluoroethylene, PTFE)基复合材料。对增强体形貌、表面微晶结构以及复合材料硬度、晶体结构、浸润性等进行了表征,揭示了CF-CNT多尺度增强体对PTFE基复合材料结晶度、表面能的影响机制,在不同往复摩擦学试验参数下测试了复合材料的摩擦系数与磨损率,对摩擦过程各个阶段进行细致分析并提出了相应的摩擦磨损机制,结果表明:稀土LaCl3表面处理方法相对传统方法具有不损伤纤维、无毒害的工艺优势;多尺度增强PTFE基复合材料磨损率降低了75.3%,优于同类研究;CF-CNT多尺度增强复合材料较小的表面能降低了起始摩擦系数;多尺度结构及La(III)提高了CF-CNT增强体与PTFE基体的界面结合性能,使材料在摩擦过程中不易产生大块硬质磨粒,并形成强度与稳定性较高的转移膜;复合材料摩擦学行为受往复频率及载荷影响显著,而且在高往复频率及低载荷下磨损率较低。本研究采用稀土LaCl3表面处理方法合成CF-CNT多尺度增强体并将其用于提高聚四氟乙烯复合材料摩擦学性能,所得结论为高性能树脂基复合材料的设计提供了参考。

     

    Abstract: To avoid the fibre damage and serious pollution caused by the traditional chemical methods, this study synthesized the carbon fibre (CF)-carbon nanotube (CNT) micro-nano multiscale reinforcer by rare-earth LaCl3 surface treatment method, and then prepared CF-CNT multiscale reinforced polytetrafluoroethylene (PTFE) composites via sintering process. The morphology and surface microcrystalline structure of the reinforcer, and the hardness, crystal structure and wettability of the composite were characterized, and the influence mechanism of the CF-CNT multiscale reinforcer on the crystallinity and surface energy of the PTFE composite was revealed. The coefficient of friction and wear rate of the composites were tested under different reciprocating tribological test parameters, every stage of the friction process was thoroughly discussed with the proposition of corresponding friction and wear mechanism. These results demonstrate that: the avoidance of fibre damage and toxic raw materials distinguishes the proposed CF-CNT reinforcer synthesis method from the traditional methods. The lower surface energy of CF-CNT reinforced composite decreases its initial friction coefficient. The wear rate of the CF-CNT reinforced composite is reduced by 75.3%, which is superior to the counterpart in similar studies. The multiscale structure and La(III) on CF-CNT improve the interface bonding performance of the CF-CNT reinforced composites, prevent the generation of large and hard wear debris during the surface yielding process as well as promoting the formation of high strength and stable transfer film. The tribological behaviors of the CF-CNT reinforced composites is sensitive to the reciprocating frequency and load, the higher frequency and lower load favour the lower wear rate. This study synthesized CF-CNT multiscale reinforcer via rare-earth LaCl3 surface treatment method to enhance the tribological properties of PTFE composite, the obtained research conclusions are instructive for the design of high-performance polymer composite.

     

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