Deprotonation-induced liquid-solid co-precipitation of AF/PEEK composites with high toughness and anti-wear performance

Aromatic polyamide fibers (AF) offer high strength and low density but suffer from poor interfacial affinity with polyether ether ketone (PEEK) due to their high crystallinity and inert surface, leading to inhomogeneous products and degraded mechanical properties. Here, a deprotonation-induced liquid–solid co-precipitation strategy is proposed to fabricate homogeneous AF/PEEK composites. Deprotonation reversibly disrupts intermolecular hydrogen bonds in AF, enabling their dissociation in the liquid phase. Subsequent dispersion of PEEK powders followed by co-precipitation yields homogeneous composite powders, which are then sintered into bulk materials. The effects of AF content (0–20 wt%) on microstructure, mechanical, and tribological properties were systematically investigated. At 10 wt% AF content, the composite achieves optimal performance, with a fracture toughness of 2.74 MPa·m^1/2 (97 % improvement over neat PEEK), a tensile strength of 83.64 MPa (18 % improvement) and a low wear rate of 3.44 ± 0.27 × 10⁻⁶ mm³/N·m (42 % reduction). Mechanistic analysis reveals that deprotonation introduces carboxyl groups onto the AF surface and facilitates π-π stacking with PEEK, establishing strong interfacial bonding that effectively dissipates fracture energy. Additionally, uniformly dispersed AF promotes a stable protective tribolayer, suppressing debris spalling and third-body wear. This work achieves simultaneous optimization of AF dispersion and interfacial bonding, offering a new pathway for high-performance thermoplastic composites.