Particle Filled Polyether Ether Ketone Composite Materials, Bio-tribological Properties

Aseptic loosening of the artificial joint is a difficult problem to the development of artificial joint for long. Therefore improving the ability of wear resistance of joint materials is very valuable to improve the service years of artificial joint. Poly(ether-ether-ketone)(PEEK) possesses not only thermal stability, innocuity property and good resistance to solvent attack but also good wear resistance. Recently, PEEK has been called super plastic, and it has been widely used as a kind of biocompatibility material. In this paper, PEEK is modified with the filling of nano Al₂O₃ and micron UHMWPE powders. The effects of powders that filled in on the tribological properties of PEEK are investigated.The pure PEEK and a series of PEEK-base composites reinforced by different kinds of powders are prepared by means of heat moulding. The hardness and wetting angle of PEEK composites are measured, and it will be the reference of the research on the tribological properties of PEEK composites. The structure and crystallization changes of PEEK with the filling of powders are studied by IR test. The tribological properties are investigated under three different lubricating conditions including distilled water, saline and serum by sliding against CoCrMo alloy ring and Si₃N₄ ceramic ring. The effects of amount, size, kind of powder that filled in, lubrication and the ring that PEEK composite slides against on the tribological properties of PEEK composites are studied. The morphologies of the worn surfaces are observed with optical microscope to analyze the tribological behavior of PEEK composites synthetically.As a result, the hardness, wetting and crystallization ability of UHMWPE are all advanced with proper amount of filling powder. The results of friction experiment show that the wear resistance of PEEK is improved with the filling of powder. When different powders are filled in, PEEK composite that filled in UHMWPE exhibits very low friction coefficient; PEEK composite that filled in nano Al₂O₃-01 exhibits very low wear rate. When different lubrication is used, distilled water show very effect on reducing friction coefficient; serum has very effect on reducing wear rate. When sliding against CoCrMo alloy ring, friction coefficient of the composites is lowest and wear rate of composites is highest. But, the result is opposite when sliding against Si₃N₄ ceramic ring. On the same condition, the wear rate of composites sliding against Si₃N₄ ceramic ring is only one ninth of that sliding against Si₃N₄ CoCrMo alloy ring.