Polytetrafluoroethylene (PTFE) fiber reinforced polyetheretherketone (PEEK) composites

This work uses high tenacity expanded polytetrafluoroethylene (ePTFE) filaments as both a fiber reinforcement and a reservoir for solid lubricants. The goal is to reduce the wear of the composites by regulating the PTFE transfer. Expanded PTFE films are a porous network of PTFE nodes and fibrils, while highly oriented ePTFE filaments are aligned crystalline fibers that are regarded as high-tenacity fibers that can be woven into threads or yarns. Reported yield strength of these filaments can exceed 500 MPa. The best performing composites were those that had filaments of ePTFE aligned normal to the counterface. The wear rates obtained from the inclusion of expanded PTFE filaments were better than conventional powder filled PTFE–PEEK composites reaching values as low as K = 7 × 10−8 mm3/N m and showed stable friction coefficients below μ = 0.125 for over 2 million cycles.