ISSN   1004-0595

CN  62-1224/O4

高级检索

可熔融加工PTFE对FEP在干/湿环境中摩擦磨损性能的影响

Friction and Wear Performance of Melt-Processable PTFE/FEP Blends under Dry and Wet Conditions

  • 摘要: 为建立含氟聚合物的使用性能与干湿工作环境的关系,采用热压成型的方式制备聚四氟乙烯(PTFE)试样,并通过挤出注塑成型方法制得可熔融加工PTFE (M-PTFE)/聚全氟乙丙烯(FEP)共混物. 研究PTFE和FEP的相关性能,特别是M-PTFE/FEP共混物的力学性能以及在干、湿状态下的摩擦磨损性能. 结果表明:在研究的配比范围内,共混材料的拉伸强度随着M-PTFE含量的增加而增大. 干摩擦条件下,M-PTFE的质量分数≤20%时,增加M-PTFE含量可降低试样的摩擦系数与体积磨损率,但M-PTFE的质量分数达到30%时两个参数均会增大. 湿摩擦条件下,试样的摩擦系数和体积磨损率与M-PTFE的添加量之间无规律性,但都低于干摩擦条件的值. 对磨面形貌的SEM照片分析表明:在干摩擦条件下,增加M-PTFE添加量会促进转移膜的形成和完善,但湿摩擦会抑制转移膜的形成.

     

    Abstract: Polytetrafluoroethylene (PTFE) and perfluoroethylene-propylene copolymer (FEP) were fabricated as test specimens by hot-pressing molding and melt injection molding respectively, and their tribological properties were investigated. The results indicated that PTFE had lower friction coefficient than FEP in both dry and wet circumstance. On the basis of this research, the melt-processable PTFE (M-PTFE)/FEP blends were prepared by melt extrusion and injection molding, and comparatively characterized by x-ray diffration (XRD), differentiall scanning caloriemetry (DSC), and mechanical property measurements, especially tribological properties in both dry and wet states. The XRD and DSC results indicated that the melt-processable PTFE was well miscible with FEP matrix. The tensile strength of the blends increased monotonously with increasing M-PTFE in the studied blending range. The friction coefficient and volume wear rate of the blends, however, performed irregular trends, depending on the M-PTFE addition and testing environments. In dry friction, the friction coefficient decreased with the increase of M-PTFE addition. Whereas, the volume wear rate decreased with the M-PTFE content below 20%, and increased when the M-PTFE addition reached 30% possibly due to the high wear rate of M-PTFE. Different from the results in dry friction, both the friction coefficient and volume wear rate didn’t display a relationship with M-PTFE content under wet friction. It was observed that the friction coefficient and volume wear rate under wet environment were lower than those under dry condition. Scanning electron microscopy observation of worn surface revealed that the transfer film was formed, and became perfection with the increase of M-PTFE content under dry friction. The transfer film, on the other hand, was inhibited to some extent in the presence of water, and only shallow and narrow furrows appeared on the wet worn surface. Based on the investigation, the tribological mechanism of M-PTFE/FEP blends under dry and wet environment was probed.

     

/

返回文章
返回