Molecular dynamics study on enhancement of mechanical and tribological properties of polytetrafluoroethylene composites by incorporating hexagonal boron nitride nanosheets

Abstract

AbstractMolecular models and sandwiched friction models of pure PTFE and h‐BN/PTFE composite were respectively constructed to investigate the enhancement of mechanical and tribological performances of the polytetrafluoroethylene (PTFE) matrix by incorporating the hexagonal boron nitride (h‐BN) nanosheets as reinforcements. The simulation results indicate that increases of 36.4% in the Young's modulus, 23.6% in the bulk modulus, and 37.3% in the shear modulus of the PTFE matrix are achieved respectively by the incorporation of h‐BN nanosheets. Decreases of 3.48% and 10.27% in the Poisson's ratio and the ratio of bulk modulus to shear modulus of the PTFE matrix are also observed due to the incorporation of h‐BN nanosheets, which shows that the ductility of the PTFE matrix could be somewhat decreased with the addition of h‐BN nanosheets. Additionally, decreases of 69.23% and 69.06% in the coefficient of friction and friction stress of the PTFE matrix are obtained respectively with the introduction of h‐BN nanosheets. To provide in‐depth insight into the internal reason for these findings, the interaction energy between the PTFE matrix and h‐BN nanosheets, the MSD and diffusion coefficient of PTFE chains, and the RDF of carbon and fluorine atoms in the PTFE backbone chains were evaluated and interpreted accordingly.