Short aramid-fiber reinforced ultra-high molecular weight polyethylene

Ultra-High Molecular Weight Polyethylene (UHMWPE) is frequently used in artificial joints because of its high wear resistance. To extend the lifetime of these joints even further, it is necessary to decrease the wear rate. The wear rate may be decreased by blending UHMWPE with short aramid fibers. On account of the extremely high viscosity of UHMWPE mixing was accomplished by swirling the UHMWPE powder and the chopped fibers with compressed dry nitrogen, and a composite with fairly uniformly distributed and randomly oriented fibers was obtained by compression moulding. The failure behaviour of the composite changes from ductile for low fiber content to brittle failure for higher fiber content. The deviation of the experimental Young's modulus from the theoretical value can be explained by, among others, the void content. Preliminary results show that the wear rate of UHMWPE indeed decreases with incorporation of the aramid fibers.