Effect of Perfluoropolymers on the Anti-Wear Properties of Carbon Fiber/Polyphenylene Sulfide Composites: A Comparative Study

In this work, several perfluoropolymers (PFP), including commercial polytetrafluoroethylene (PTFE), perfluorinated ethylene–propylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and irradiated PTFE (iPTFE) were used as additives to lubricate carbon fiber (CF)-reinforced polyphenylene sulfide (PPS) composites. The tribological properties of the yielding composites were studied and correlated with the melt processability of PFPs. Although the neat FEP and PFA have higher friction coefficients when compared with neat PTFE, the composites filled with FEP and PFA additives were found to exhibit a lower friction coefficient compared to PTFE at PFP content below 10 wt %. Moreover, the iPTFE-filled composites also showed similar results as FEP or PFA filled ones, very different from PTFE at low additions. Based on the morphological investigation, we postulate that FEP, PFA, and iPTFE are melt-kneaded with PPS due to their melt processability at processing temperature, leading to the good dispersion in composites in the form of smaller deformed spheres and/or fibril bands. The well-dispersion of PFPs in composites promotes the formation and growth of the transfer film on the counterface during sliding.