Tribological behavior of UHMWPE matrix composites reinforced with PTFE particles and aramid fibers

Abstract

Ultra-high-molecular-weight polyethylene (UHMWPE) has been extensively utilized in various tribological systems due to its high wear resistance, low friction coefficient, anti-corrosion behavior and eco-friendly properties. However, the demand from the market requires further improvements to withstand the harsh conditions in the applications. For this reason, different kinds of fillers have been included in the UHMWPE matrix to produce composite materials possessing advanced properties especially against wear. Although several investigations have been carried out to develop the tribological behavior of UHMWPE based composites by using various fillers, there has been a little attention on the effect of manufacturing parameters such as molding pressure. Furthermore, polymeric fillers in the polymeric matrices have not been studied extensively as such in polymer based composites with hard fillers. For this reason, the tribological properties of the UHMWPE based composites were investigated by using different polymeric fillers such as polytetrafluoroethylene (PTFE) particles and aramid fibers in this study. The filler loadings were varied in the composites to investigate their effects on the tribological behavior. Moreover, molding pressure was changed from 100 to 300 bar in the compression molding process of the UHMWPE specimens to investigate the influence of manufacturing conditions. The tribological tests were conducted in a ball-on-disk apparatus against a tungsten carbide ball and from the results, increase in the molding pressure leads to a consolidation in the microstructures and thereby enhancing the wear performance of the specimens. Furthermore, both fillers contribute to the wear resistance of the UHMWPE matrix however, by exhibiting different mechanisms in the sliding process.