Mechanically Strong and Thermally Stable Polyimide Aerogels With Hierarchical Cellular Structure for Thermal Insulation

Abstract

ABSTRACT Crosslinked polyimide aerogel exhibits excellent mechanical properties, thermal insulation, and flame retardant properties. However, the high adiabatic properties of polyimide aerogels are attributed to their nanostructure configuration. Nevertheless, controlling the morphology of polyimide aerogel has been a scientific challenge. In this study, the high‐basicity diamine monomer 4,4′‐diaminodiphenylmethane (MDA) was introduced into the aerogel framework consisting of 4,4′‐diaminodiphenyl ether (ODA) and 3,3′,4,4′‐biphenyl tetracarboxylic acid dianhydride (PMDA). A bisamine skeleton polyimide aerogel with a custom‐assembled nanostructure was prepared by the freeze‐drying–thermal imide method. The results showed that the polyimide aerogel sample MOPI‐3 had a covalently cross‐linked three‐dimensional mesh layer chemical structure, low density (0.0733 g/cm 3 ), high decomposition temperature ( T g = 525.5°C), and low thermal conductivity (13.32 mW/(m·K)) under the condition of introducing the monomer MDA at a 50% mol ratio. It also exhibits excellent mechanical properties, bearing more than 4000 times its own weight without deformation. This work provides a new idea for researching polyimide aerogels in the field of thermal insulation, and their outstanding thermodynamic properties make them widely applicable in electronic component heat dissipation and spacecraft protection.