Wear‐Resistant 3,3′,4,4′‐Biphenyltetracarboxylic Dianhydride/Bisphenol A Dianhydride Polyimide/ MXene Composites for Lubrication Protection

The rigid biphenyl‐type polyimide possesses a thermal decomposition temperature of up to 600°C. However, its continuously rigid conjugated backbone structure leads to high brittleness and limited tribological properties, which constrain its engineering applications. In this study, a molecular structure design and nano‐reinforcement composite strategy were employed. A polyimide matrix was synthesized by copolymerizing 3,3′,4,4′‐biphenyltetracarboxylic dianhydride and bisphenol A dianhydride at a 1:1 M ratio with p‐phenylenediamine. Ti 3 C 2 T x MXene was introduced to construct an organic–inorganic composite system. At a MXene loading of 1.0 wt%, the 5% weight loss temperature and the glass transition temperature increased by 14.91% and 7.15%, respectively. Furthermore, Ti 3 C 2 T x MXene facilitates the formation of transfer films between friction pairs, thereby protecting the polyimide/Ti 3 C 2 T x MXene composites. The composite achieves the minimum friction coefficient with 0.5 wt% Ti 3 C 2 T x MXene, corresponding to a 31.58% reduction. When the Ti 3 C 2 T x MXene content reaches 0.3 wt%, the composite exhibits the lowest wear rate with a reduction of 52.04%. These results indicate that this system significantly enhances the thermal stability and wear resistance of the material.