Advances in high-temperature resistant polyimide resin and composite materials technology

The high-temperature service environments of aerospace equipment impose stringent demands on high-temperature resistant resin-matrix composites. Traditional epoxy and bismaleimide resin systems suffer from limited temperature resistance, making polyimide a core research direction of advanced high-temperature structural composites. This paper systematically elaborates the molecular structural characteristics of polyimide resins and their classification into thermosetting and thermoplastic categories. The technological evolution of NA-capped, PEPA-capped, organic-inorganic hybrid and thermoplastic polyimides is summarized, and the structural features, processing characteristics and performance deficiencies of various polyimide systems are compared. Recent research advances in matrix modification, precise molecular design, fiber-reinforced systems and multifunctional sandwich structures are comprehensively reviewed. The advantages and limitations of modification strategies including heterocyclic structure introduction, bulky side group grafting, flexible chain segment construction and organic-inorganic hybridization are analyzed. Meanwhile, the interfacial regulation, high-temperature service performance and engineering applications of carbon fiber and quartz fiber reinforced polyimide composites are concluded. Current technical bottlenecks, such as the inherent contradiction between thermal resistance and processing fluidity, high preparation cost, insufficient interfacial stability under extreme high temperature, and difficulties in molding large-scale components, are clarified. Finally, future development trends are proposed from the aspects of precise molecular design, low-cost forming process optimization, material-process collaborative matching and integrated structure-function design. This work provides a systematic reference for the iterative research and engineering application of high-temperature resistant polyimide composites in aerospace fields.