Synthesis of polyimides with lower H₂O‐absorption and higher thermal properties by incorporation of intramolecular H‐bonding

Abstract

Abstract To introduce intramolecular hydrogen bonds in the polyimides (PIs), 5(6)‐amino‐2‐(5‐aminopyridin‐2‐yl)‐benzimidazole (PyPABZ) were designed and synthesized. The intramolecular interaction was indicated by Fourier transform infrared when different copolyimides were prepared with 4,4′‐oxydianiline and PyPABZ. These modified poly(benzimidazole imide)s eliminate the problem of high water absorption for benzimidazole (BI)‐containing PIs in the materials applications. Moreover, the high packing coefficient and rigidity of these copolyimides caused by the strong intramolecular interaction from the H‐bonding and the resulting PIs exhibited outstanding thermal properties such as high glass‐transition temperature ( T g ) and low coefficient of thermal expansion.