Effect of the reduced graphene oxide on the tribological behavior of UHMWPE/rGO nanocomposites under sliding contact conditions

In this work, the effect of the addition of reduced graphene oxide (rGO) nanofillers to UHMWPE was investigated. The UHMWPE/rGO nanocomposites were prepared at rGO contents of 0.010, 0.10, 0.25, and 0.50 wt%. The morphological, mechanical, and surface properties of the nanocomposites and the neat UHMWPE were evaluated and related with their tribological behavior. For that, DSC, SEM, contact angle, MO, and profilometry techniques, besides shore D hardness tests, instrumented indentation tests and pin-on-disc sliding wear tests were performed. The results showed that nanocomposites with rGO contents of 0.10 and 0.25 wt% exhibited higher crystallinity degree than the neat UHMWPE, which improved significantly their mechanical and tribological behavior through increases of around 40% in the instrumented hardness and the elastic modulus, and a significant reduction of up to 48% in the coefficient of friction when compared to the neat UHMWPE. Additionally, the presence of rGO decreased the work of adhesion of the nanocomposites/counterface pairs, resulting in friction and wear mechanisms changes in comparison with the neat polymer.