Green synthesis of polyimides and their CNT based nanohybrid shish-kebabs through reaction-induced crystallization of nylon-salt-type monomers in glycerol

Abstract

A green approach to the synthesis and morphological control of high performance polyimides and their nanohybrid shish-kebabs in glycerol through reaction-induced crystallization of nylon-salt-type monomers was reported. Crystalline polyimide nanoplates can be observed by direct polycondensation of pyromellitic acid with various kinds of aliphatic or aromatic diamines. With the existence of carbon nanotubes, the polyimides can be successfully decorated on the surface of CNTs through a reaction-induced hetero-epitaxial crystallization process, and resulted in novel polyimide/CNT nanohybrid shish-kebabs (NHSKs) structures. The morphologies of the NHSKs can be fine-tuned through changing the concentration of monomers or the reaction temperature, especially through the introduction of dynamic imine chemistry, the formation process of NHSKs can be attributed to a soft epitaxy mechanism. Thus a green approach for the synthesis of high performance polyimides and their CNT based nanohybrid structures was explored, which should be of great value for their applications in high performance reinforced nanocomposites.