A green and scalable method for producing high-performance polyimide aerogels using low-boiling-point solvents and sublimation drying

Abstract

Polymeric aerogels have great potential in numerous fields because of their unique combination of thermal and electrical properties, and lightweight porous structures. However, the laborious supercritical CO2 drying method required for making these aerogels limits their commercial availability. Here we demonstrate a green and scalable method for preparing high-performance polyimide (PI) aerogels using a low-boiling-point solvent mixture of tetrahydrofuran/methanol, and especially using sublimation drying instead of laborious supercritical CO2 drying. The monolithic and powder polyamic acid aerogels can be prepared easily; after thermal imidization, PI aerogels with nanofibrous morphology, low density and high thermal stability can be obtained. This green, scalable and cost-effective process will facilitate the application of high-performance PI aerogel materials in many fields, in particular those in which high-temperature resistance is important. The laborious supercritical CO2 drying method limits the commercial availability of polymeric aerogels. Here we demonstrate a green and scalable method for the preparation of high-performance polyimide (PI) aerogels using low-boiling-point solvent mixture of tetrahydrofuran/methanol, and especially using sublimation drying instead of supercritical CO2 drying. Monolithic and powdery PI aerogels with nanofibrous morphology, low density and high thermal stability can be prepared facilely and thus facilitate their applications in many fields, especially high-temperature resistance, which are of essential importance.