Synergistic friction and wear reduction in PEEK/PTFE composites through P‑MoS₂ and K‑BN‑OH integration

Polyetheretherketone (PEEK) possesses excellent corrosion resistance, moderate friction properties, and high‑temperature stability. However, under severe operating conditions, its coefficient of friction (COF) and wear rate increase significantly, limiting broader application. In this work, P‑MoS₂ was synthesized in situ on a PEEK matrix using a hydrothermal method, while K‑BN‑OH was prepared via surface grafting with a coupling agent. Both fillers were then blended with a PEEK/PTFE matrix to produce a novel PEEK/PTFE/P‑MoS₂/K‑BN‑OH composite. Orthogonal experiments identified the optimal composition of PEEK/PTFE/P‑MoS₂, which exhibited the best overall performance. The effect of K‑BN‑OH content on the mechanical, thermal, and tribological properties of the composites was systematically studied. Tribological behavior under varying conditions was analyzed to elucidate wear mechanisms and filler synergy. Results show that the composite with 25% PTFE and 5% P‑MoS₂ achieved the most balanced performance: elastic modulus (1414.62 MPa), compressive strength (127.81 MPa), COF (0.108), and wear rate (1.81 ×10⁻⁶ mm³/N·h) decreased by 22.58%, 35.82%, 73.13%, and 59.78%, respectively, compared to pure PEEK, while creep strain (2.77%) increased by 95.62%. Further addition of 3% K‑BN‑OH enhanced mechanical and thermal properties: elastic modulus rose to 1520.13 MPa, compressive strength to 131.33 MPa, creep strain fell to 1.82%, and thermal conductivity reached 0.294 W/m·K. The average coefficient of friction(ACOF) declined to 0.094, though wear rate rose slightly to 2.26 × 10⁻⁶ mm³/N·h. Tribological tests revealed that wear rate increased with rotational speed, while ACOF showed a non‑monotonic trend, first decreasing and then increasing. With increasing load, both ACOF and wear rate initially decreased before rising, reaching minima at 20 N (0.077 and 2.09 ×10⁻⁶ mm³/N·h, respectively). Molecular dynamics simulations elucidated that PTFE formed a lubricating film through interfacial enrichment, while MoS₂ enhanced matrix ordering and promoted interfacial slip via π-π stacking and C-S bonding. In contrast, h-BN disrupted the synergistic lubrication network established between PTFE and MoS₂ due to its spatial blocking effect. This work systematically elucidates the synergistic mechanisms of fillers from the microscopic level to macroscopic performance, providing a theoretical basis for the design of high‑performance PEEK composites tailored to specific operating conditions.