High-strength and high-temperature-resistant multilayer interconnected polyimide paper derived from anisotropic aerogel via a hot-extrusion strategy for aerospace applications

The continuous improvement of papermaking technology has attracted widespread attention. However, the prevention of high-temperature decomposition and a subsequent decline in mechanical strength is still a significant challenge with current papermaking technology. Herein, a newly developed multilayer interconnected polyimide aerogel-based paper was successfully prepared via an anisotropic aerogel hot-extrusion strategy. Precursor solutions of highly rigid benzimidazole units containing intermolecular hydrogen bonds and linear rod-like benzimide units were first prepared. Anisotropic precursor polyimide (PAAS) aerogels with a thickness of 3 mm were then manufactured by unidirectional freeze-drying. Then, aerogel-based papers with a thickness of 40 μm and microstructure multilayer interconnected properties were obtained by a hot extrusion strategy and a thermal imidization process. This polyimide structural paper exhibited excellent thermal and mechanical properties. Through the design of micro and macro structures, the tensile strength of the aerogel-based paper was much higher than that of commercial paper at both room temperature and 400 ℃. This aerogel-based paper also exhibited high-temperature cycle stability, high flexibility, and good stretchable bending properties. The successful preparation of this aerogel-based paper demonstrates the feasibility of the hot extrusion strategy. This work provides a new papermaking technology method and broadens the application field of paper.