Polymer-based materials show to be of increasing interest in replacing metal based materials in tribological applications due to their low weight, cost and easy manufacturability. To further reduce the environmental impact of these bearing materials recyclability is becoming more crucial, stimulating the need for high performing thermoplastic materials. In this study, polyphenylene sulfide (PPS) composites were prepared in an effort to enhance its tribological properties. Short carbon fibres (SCFs), graphene oxide (GO) and nano diamonds (NDs) as well as polytetrafluoroethylene (PTFE) were used as micro and nano reinforcements. The addition of SCFs especially decreased the linear coefficient of thermal expansions while enhancing the micro hardness and wettability of the polymer. Under water lubricated conditions, a decrease in friction up to 56% and a reduction of wear rate in the order of 10³ was observed by the addition of SCF. The reduction in friction and wear was further enhanced by the addition of NDs, providing a synergistic effect of the reinforcements in micro and nano scale. By testing the individual reinforcements under dry conditions, PTFE and SCFs were especially effective in reducing friction while the release and consequent abrasion of NDs and SCFs increased the wear under a higher contact pressure.

An UHMWPE‐based multiscale composite containing graphene oxide, nanodiamonds, and short carbon fibres has shown excellent performance under distilled water lubrication. However, it is crucial to evaluate its tribological performance under conditions which more accurately represent the final application. In this study, the tribological performance of the developed UHMWPE‐based multiscale composite is evaluated and compared with neat UHMWPE under different lubricating conditions: no lubricant (dry), in seawater (SW) and in an environmentally acceptable lubricant (EAL). While neat UHMWPE displays a lower friction and wear in dry conditions, the multiscale composite performs better under SW and EAL lubrication. A maximum reduction in friction coefficient of 77% and specific wear rate of 88% are obtained in SW. Under EAL lubricated conditions, the multiscale composite has a maximum reduction in specific wear rate of up to 75%.