Aramid Reinforced Polyimide Aerogel Composites with High‐mechanical Strength for Thermal Insulation Material

Polyimide (PI) aerogels have attracted extensive attention in the field of building insulation due to their low-thermal conductivity, excellent thermal stability, and great flame retardancy. However, poor mechanical strength was the main factor which restrict their extensive applications. Herein, we report a simple strategy to prepare thermal insulating aramid/PI aerogel composites with high mechanical strength as well as flame retardancy through mold-forming and freeze-drying methods. A series of lightweight aramid felt reinforced PI aerogel composites were prepared by interfacial adhesion between aramid fiber and PI aerogel, and the most striking sample PI-3 displayed favorable comprehensive performance, including good tensile property (8.88 MPa), bursting performance (299 N), thermal insulation property (0.0341 W/m center dot K), thermal stability and self-extinguishing behavior. This strategy can be applied to many types of organic aerogel materials that used in the aspects of insulation and thermal protection in extreme environments.