Experiments and Atomic Insights on the Tribological Properties of Functionalized Graphene-Reinforced Polyetheretherketone/Polytetrafluoroethylene Composites

Abstract

This study explores the influence of functionalized graphene nanosheets (GNSs) on the tribological behavior of polyetheretherketone (PEEK)/polytetrafluoroethylene (PTFE) composites. To this end, pure GNS (PGNS) and GNS grafted with hydroxyl, carboxyl (COOH-GNS), and amino functional groups are prepared to fabricate PEEK/PTFE composite samples for friction experiments. The microstructure of the worn surface and energy dispersive spectroscopic distribution of the dual-surface transfer film are analyzed. The experimental results demonstrate that the COOH-GNS-reinforced PEEK/PTFE composite samples exhibit outstanding tribological properties. Specifically, the wear rate decreases by 20.9% compared to that of the PGNS-reinforced PEEK/PTFE composite samples, and a denser transfer film is formed on the dual surface. Additionally, molecular dynamics simulations are used to simulate the friction process and investigate the mechanism by which functionalized GNS enhances the tribological properties of the PEEK/PTFE composites. The simulation results reveal that the functional groups remarkably enhance the interaction between the GNS and the PEEK/PTFE composites, reduce the temperature and atomic concentration at the friction interface, and weakene the interaction between the PEEK/PTFE molecular chains and the friction pair, thereby improving the wear resistance of the PEEK/PTFE composites. Thus, this study provides a theoretical basis for the development of PTFE-based composites.