Interconnected expanded graphite/stearic acid networks for self-lubricating PA6 composites with excellent heat dissipation performance

The improvement in social production efficiency demands increasingly faster mechanical operation speeds. However, under high-speed friction conditions, the frictional heat generated by nylon 6 (PA6) components is difficult to dissipate efficiently, leading to severe wear and subsequently threatening the safe operation of the equipment. In this work, interconnected expanded graphite/stearic acid (EG/SA) networks in PA6 composites were constructed to achieve fast frictional heat dissipation and self-lubricating properties by a simple hot-pressing method. The synergistic lubrication of EG and SA results in PA6 composites with a low coefficient of friction (COF) of 0.12, a 74.5% reduction compared to pure PA6. The low COF reduces the generation of frictional heat, while the conduction and absorption of frictional heat by the EG/SA network accelerates the dissipation of frictional heat, ultimately lowering the contact temperature from 106.9°C to 40.6°C. The specific wear rate of the PA6 composite is as low as 1.7 × 10 −5 mm 3 N −1 m −1 , which is 90.1% lower than that of pure PA6. This study provides a new solution for the rapid dissipation of frictional heat in polymer composites under harsh operating conditions and broadens the application range of wear-resistant polymer composites. Highlights Expanded graphite (EG) prevents stearic acid from leaking through adsorption. The interconnected EG network transfers frictional heat to stearic acid. The phase transition of stearic acid can absorb heat and promote lubrication. The low COF and high heat dissipation make PA6 composites highly wear-resistant.