Multifunctional roles of layered double-hydroxides in self-lubricative carbon fiber reinforced PEEK-PTFE composites

Carbon fibers (CFs) reinforced poly(ether-ether-ketone) (PEEK) composites show great potential in replacing steel structural materials. However, the risky interfacial connection between CFs and PEEK usually leads to an inferior tribological performance, thereby severely restricting further application in moving parts. In this study, Co-based layered double-hydroxides (Co-LDHs) are hydrothermally grown onto the surface of CFs and then blended with PEEK-PTFE (Ti₃C₂T_x) (PTFE: polytetrafluoroethylene; Ti₃C₂T_x: titanium carbide MXene with surface terminal groups T) to fabricate PEEK(CF)-PTFE(Ti₃C₂T_x) composites. Their mechanical properties and tribological performance are studied. The Co-LDHs not only strengthen the composites but also improve the tribological performance via the polishing, anchoring, and synergistic effects. Eventually, the compressive strength of the composites can be increased by 20.90 % at maximum. Meanwhile, an ultra-low coefficient of friction of 0.064 ± 0.008 with a wear rate of (4.69 ± 0.90) × 10⁻⁶ mm³/N⋅m is achieved. The results indicate the great potential of LDHs in modifying CFs for self-lubricating polymer-based composites.