PTFE composite with high tribological stability via a single multi-functional filler Ca/Al-layered double hydroxide

To address the insufficient wear resistance and load-bearing capacity of polytetrafluoroethylene (PTFE), this study introduces calcium–aluminum layered double hydroxides (Ca–Al LDHs) as the sole functional filler. By varying the LDH content, we investigated its effects on the tribological properties, thermal stability, and mechanical performance of PTFE composites. Combined with experimental characterizations including Fourier-transform infrared spectroscopy, density functional theory (DFT) calculations, and molecular dynamics simulations, it is found that a hydrogen-bonding network can be formed between Ca–Al LDHs and the PTFE matrix. Furthermore, LDHs can induce interfacial tribochemical reactions during friction, which significantly promote the formation of a stable and continuous transfer film. The results show that the addition of layered double hydroxides enables the composite to achieve a friction coefficient of 0.179 and a wear rate as low as 0.289 × 10 −13 m 3 /(N·m), which is reduced by a factor of 57.2 compared with pure polytetrafluoroethylene. The composite exhibits a tensile strength of 22.2 MPa, a compressive strength of 26.4 MPa, and a Young's modulus of 311.5 MPa. Its thermal decomposition rate at high temperatures is decreased, thereby improving the high-temperature service performance of the composite. This composite is suitable for wear-resistant and friction-reducing applications under high-temperature conditions and shows great potential for engineering applications in harsh service environments.