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A polymer–polymer tribological pair made of antifriction ultrahigh molecular weight polyethylene (UHMWPE) and high-strength polyetheretherketone (PEEK) composites was proposed and tested in various operating conditions (lubrication medium and dry friction at a deficit of synovial fluid in the joint). The selection of fillers for UHMWPE and PEEK was substantiated in steps proceeding from the data of systematic mechanical and tribological tests. The optimal composition of the composites, suggesting the possibility of manufacturing customized joint prosthetic implants using additive manufacturing technologies, is determined. It was shown that the PEEK (pin)-on-UHMWPE (disk) tribological pair is well compatible, characterized by a low coefficient of friction (f = 0.02), and zero wear found by optical microscopy observations. The friction of non-filled UHMWPE on PEEK reinforced with two types of carbon fibers (milled carbon fibers, 30 wt % and CNT, 2.5 wt %) is checked. It is shown that carbon nanotubes are efficient fillers for PEEK in the UHMWPE–PEEK tribological pair under dry sliding friction at a deficiency of synovial fluid. [ABSTRACT FROM AUTHOR]

The structure and mechanical and tribological properties of composites based on a thermoplastic matrix of polyetheretherketone (PEEK) loaded with carbon fibers of various (nano-, micro and millimeter) sizes were studied. The research is aimed at developing composites applicable for use both in metal–polymer and ceramic–polymer tribojoints, including endoprostheses. It is shown that the surface layer of the PEEK composite loaded with carbon nanofibers can play a damping role in the friction process. This ensures an increased in wear resistance by 1.5–2 times. Carbon fibers of micron and millimeter length play a reinforcing role. Thus, the wear resistance of PEEK composites can be increased up to seven times in metal–polymer tribojoints, while this is reduced by 16 times in ceramic–polymer tribojoints. It is shown that by choosing the type and weight fraction of fiberlike fillers (carbon nano/micro/millimeter fibers) in PEEK matrix, the tribological and mechanical properties can be purposefully increased. This makes it possible to expand areas of application and product range for tribojoints in mechanical engineering and medicine, including those formed using additive technologies. [ABSTRACT FROM AUTHOR]

In order to develop dispensable materials for additive manufacturing technologies, the structural and functional analysis of antifrictional polymer-polymer blends based on ultrahigh-molecular weight polyethylene (UHMWPE) are performed. The problem of the optimal selection of polymer plasticizers from the commercially available thermoplastic is solved in order to improve the extrudability of UHMWPE. It is shown that the effective plasticizing filler for UHMWPE from the standpoint of maintaining its tribological and mechanical characteristics and providing the required melt flow index is a double mixture of 10 wt % HDPE-g-SMA + 10 wt % PP. Using the developed materials will make it possible to manufacture parts of a complex shape for tribojoints, including endoprostheses, by the 3D printing method. [ABSTRACT FROM AUTHOR]