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

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. Graphical The polyimides derived from 5(6)-amino-2-(5-aminopyridin-2-yl)-benzimidazole (PIs–PyPABZ) were achieved with the presence of intramolecular hydrogen bonding. These modified co-poly(benzimidazole imide)s exhibited lower H 2 O-absorption and higher thermal properties depending on the intramolecular H-bonding content.