Tribological properties of perfluoropolymer fiber filled carbon fiber/polyphenylene sulfide composites: Effect of in‐situ fibrillated fiber or split fiber

Abstract In this study, carbon fiber (CF) filled polyphenylene sulfide (PPS) composites are lubricated with perfluoropolymer (PFP) fiber by melt‐blending. The effect of double fibers (CF‐PFP fibers) on the tribological properties of PPS composites has been carefully investigated and correlated under various sliding conditions. The results indicated that the tribological performance of PPS composites with double fibers is better than that of the composites with a single fiber, especially under severe conditions. Mechanism exploration suggests that a double‐fiber hybrid structure between a hard CF and a soft PFP fiber could tightly entrap the CF by fibril entanglement, thus preventing the CF from being stripped out of the matrix under the steel ring shearing force. Under optimized conditions, the average friction coefficient of composites with PFP fiber is only about 0.1 at 300 N load under 200 rpm, even lower than half of the average friction coefficient of the composites with PTFE powder under the same condition. Notably, compared to commercial split PFP fibers, the in‐situ formed PFP fibers with more uniform distribution significantly improve the tribological properties. This work open up a novel perspective for improving the tribological performance of composites by systematically regulating the microstructure of self‐lubricating fibrous additives. Highlights PFA is subject to in‐situ fibrillation during melt blending. Fibrous PFP effectively improves the tribological properties of PPS/CF composites. The in‐situ formed PFP fiber contributes to better tribological properties. The double‐fiber hybrid structure prevents the CF from being sheared out. The number of processing cycles affects the tribological properties.