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In this work, the wear behavior of the mechanical coupling between the biomedical polymer ultrahigh molecular weight polyethylene (UHMWPE) and the titanium-aluminum-vanadium alloy pin (Ti4Al6V) manufactured by electron beam melting (EBM) is investigated. Pure and oxidized graphite fillers is added to the UHMWPE matrix to boost the wear resistance. The tribological test is performed in dry and under the action of various lubricating media (distilled water [DW], simulated synovial fluid [SSF], and natural bovine serum [NBS]) in order to investigate their effects on wearing. The physical-mechanical characterization results show a progressive increase in wear resistance of more than 60% in the nanocomposite (UHMWPE/GO) with the addition of paraffin oil (PO) compared to the UHMWPE and higher under NBS lubricant (more than 80%). The observed wear action is reduced in the order Dry > DW > SSF ≥ NBS, thereby lowering the debris production.

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Biopolyesters, pure and mixed with a compatibilizer, are exposed to UV-C radiation in the interval 4-32 h. UV-C rays act as germicides and antibacterial on biomedical materials. The mechanical and physical characterization tests have shown how all the materials, pure and mixed, undergo UV-C photodegradation even if in a different way. The change in the structural order of the polymer, the embrittlement, and the change in the surface wettability of the water/blood is lower in the blend than in pure polymers. This is thanks to the cross-linked structure of the mixture, which is more thermally stable, mechanically resistant, and more hydrophobic than the individual components.

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The proposed research work is addressed to the study of the wear behavior of Ultra High Molecular Weight Polyethylene (UHMWPE) under the contact with a rounded pin in Ti6Al4V alloy, which is largely used for production of the last generation of prosthetic implants by electron beam manufacturing (EBM). The wear tests of UHMWPE in contact with a Ti6Al4V pin are carried out dry or in the presence of lubricants fluids that are characterized by tribological tests, wet-ability measurements, and morphological observations of the contact surfaces. UHMWPE wear resistance improves in conditions of lubrication in the order: dry < distilled water < synthetic synovial < bovine serum, according to wettability results. As suggested by the track profiles, the contact action in dry can be mainly due to shear stress while that in lubricant mainly to compressive stress.