Effect of Protein Interactions on the UHMWPE Composites After the Multidirectional Wear Test

Abstract Recent studies have found a rapid increase of ultrahigh molecular weight polyethylene (UHMWPE) wear in the presence of proteins from the synovial fluid. This is due to the high hydrophobicity surface of UHMWPE which allows the proteins to get interacted and adsorbed to the UHMWPE surface. Moreover, since UHMWPE has low thermal conductivity, the heat elevated produced from the articulating contact surfaces would be slowly dissipated and protein structure becoming denatured. The denatured proteins were claimed could increase the adhesive wear response. Thus, the main objective of this study is to evaluate the influence of the graphene oxide (GO) and graphite flake (GF) on the UHMWPE’s heat dissipation and wettability characteristics in regards to reducing the protein denaturation effect on the surface. The surface properties were characterized by using surface energy evaluation, zeta potential, and Fourier Transform Infra-red (FTIR). Following that, wear properties of each UHMWPE composite were evaluated by using a multidirectional pin-on-disc wear test under a lubricated condition. The worn surface of each pin sample was evaluated, and the dominating factors of wear properties were determined. In addition to that, the effect of protein absorption on the UHMWPE composites was also evaluated in this study. The results show both fillers (GO and GF) had no effect in altering the UHMWPE composites’ physicochemical properties. The improvement of UHMWPE composite’s wear properties was discovered to be primarily dominated by the existence of GO filler (1.0 wt%) near the sliding surface has improved the subsurface strength of the material and heat dissipation effect which reduces the denaturation of the proteins.