Mechanically strong and tough polyimide aerogels cross-linked with amine functionalized carbon nanotubes synthesized by fluorine displacement reaction

Abstract

Polyimide aerogels generally face problems of shrinkage and collapse of pore structure during preparation, resulting in poor macro-structural integrity and mechanical properties. Towards these problems, polyimide composite aerogels with three-dimensional porous network structure, outstanding mechanical and thermal properties have been synthesized by utilizing high grafting ratio of amino-functionalized carbon nanotubes (CNTs) prepared by fluorine displacement reaction in this study. All aerogel samples exhibited the network structure composed of highly interconnected nanofibers. Most importantly, the compression modulus of the PI aerogel reached to 47.3 MPa with the addition of amino-functionalized CNTs, which was 1126% higher than that of the linear PI aerogel. The prepared PI/CNT-NH2 composite aerogels can still maintain the original compressive modulus of 96% under high temperature conditions. These results indicate that the PI composite aerogels could exhibit great potential in aerospace applications as high-performance and lightweight porous materials.