Tribological behavior of graphene oxide filled melt-processable polytetrafluoroethylene/perfluoroethylene-propylene copolymer blends

In order to improve the tribological performance of perfluoroethylene- propylene copolymer (FEP), two modifiers, melt-processable polytetrafluoroethylene (M-PTFE) with a low friction coefficient and graphene oxide (GO) with wear resistance, were added into FEP in the fixed M-PTFE/FEP weight ratio of 1/4 to prepare composites. The formed GO/M-PTFE/FEP composites were evaluated in terms of friction coefficient and volume wear rate. The results indicated that the highest tensile strength have appeared at GO addition of 0.15 wt%, while the elongation at break emerged at 0.20 wt% GO. The friction coefficient and wear rate of composites decreased initially and then increased with increasing GO addition. During friction, free radicals were generated by the scission of the fluorinated molecular chain under imposed shear force and thermal striking, and subsequently reacted with oxyl to form peroxy radicals. In this manner, iron carbides were eventually formed on the counterpart surface. In addition to direct transfer and deposition on the friction tracks of the counterpart, GO embedded in the perfluorinated matrix could be transferred to the surface of the steel ring during friction.