Superior tribological performance of PEEK composites reinforced with grafted versus virgin UHMWPE

Purpose This study aims to investigate the tribological performance of polyether ether ketone (PEEK)-based composites reinforced with grafted UHMWPE and the effect of acrylic acid grafting on interfacial adhesion with PEEK. Design/methodology/approach PEEK-based composites containing 1.0–10.0 wt% grafted or virgin UHMWPE were prepared by hot pressing. Their friction and wear behaviors were examined using tribological testing, scanning electron microscopy (SEM) and molecular dynamics simulations. Findings PEEK composites reinforced with grafted UHMWPE generally exhibited lower friction coefficients, wear rates and surface roughness than those containing virgin UHMWPE. Among the tested formulations, the composite with 2.0 wt% grafted UHMWPE showed the lowest friction coefficient and wear rate, with reductions of 21% and 30% under 40 N, respectively, compared to the composite with 2.0 wt% virgin UHMWPE. Molecular dynamics simulations revealed that grafted UHMWPE possessed higher interaction energy with the PEEK matrix and greater adsorption energy on Fe surfaces than virgin UHMWPE, which is consistent with the observed tribological behavior. Originality/value This study demonstrates that grafted UHMWPE effectively enhances the tribological performance of PEEK composites and exhibits higher interaction energy with the PEEK matrix than virgin UHMWPE, thereby providing valuable insights for the design of self-lubricating polymer composites for demanding tribological applications.