Crab Leg-Inspired Poly( p -phenylene benzobisoxazole) Hybrid Fibers for Boosting the Tribological Performance of UHMWPE Composites

Abstract The performance of ultra-high-molecular-weight polyethylene (UHMWPE) is frequently limited by issues such as low strength and wear resistance. Inspired by the hierarchical structure of crab legs, this study develops a hybrid fiber filler designed to synergistically enhance the tribological and mechanical properties of UHMWPE composites. The filler (PBO@PDA@ZnO) architecture utilizes poly(p-phenylene benzobisoxazole) (PBO) fibers as a rigid structural skeleton, employs polydopamine (PDA) as a functional intermediate layer, and incorporates uniformly loaded zinc oxide (ZnO) nanoparticles on the surface to create a “rigid skeleton-functional particle” system. The results indicate that the PBO@PDA@ZnO hybrid filler significantly optimizes both mechanical and tribological performance. Specifically, the UHMWPE composite reinforced with 1 wt % filler exhibits the best overall performance, with the elongation at break increasing from 650% to 850% while simultaneously improving tensile strength. Furthermore, under both low and high load conditions, the friction coefficient of the UHMWPE composite is all reduced by over 60%, and the wear rate is decreased by an order of magnitude, with the lowest value reaching 8.46 × 10–7 mm3/N·m. This superior performance is attributed to the synergistic effects of fiber reinforcement, stable transfer film formation, and the “micro-bearing” rolling effect of the ZnO nanoparticles. This study provides a biomimetic strategy for the fabrication of high-performance self-lubricating UHMWPE composites.