Evaluation of Tribological Properties of Organoclay Reinforced UHMWPE Nanocomposites

The current study is aimed to investigate the tribological properties of ultrahigh molecular weight polyethylene (UHMWPE) reinforced with organoclay Cloisite (C15A). Nanocomposites are prepared using a high energy ball milling process followed by hot pressing. Three different loadings of 0.5 wt.%, 1.5 wt.%, and 3 wt.% of C15A, respectively, are used as reinforcement. Results from the ball-on-disk wear tests showed that nanocomposites reinforced with 1.5 wt.% of C15A exhibited best wear resistance and lower coefficient of friction (COF), with C15A reducing the wear rate by 41% and the COF by 38%, when compared to the pristine UHMWPE. These improvements are attributed to the uniform dispersion of the nanosized clay platelets preventing large-scale material removal and formation of a thin tenacious, continuous transfer film on the counterface for C15A organoclay composites. X-ray diffraction (XRD), scanning electron microscopy (SEM), and optical profilometry are used to characterize the morphology of the nanocomposites and the wear tracks. SEM images of worn surfaces indicated more abrasive wear for the case of pristine UHMWPE as compared to organoclay composites.