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.