Synthesis and characterization of new thermally stable polybenzimidazoles and poly(amide-benzimidazole)s

Benzofuro[2,3-b]benzofuran-2,9-dicarboxyl-bis-phenylamide-4,4′-dicarboxylic acid was synthesized as a new monomer, and characterized by means of IR, 1HNMR and MS spectroscopy. A series of polybenzimidazoles (PBIs) were prepared from this diacid that were considered as poly(amide-benzimidazole)s and also, some new PBIs were synthesized from benzofuro[2,3-b]benzofuran-2,9-dicarboxylic acid and several aromatic tetraamines by solution polymerization method in polyphosporic acid as solvent. Thermal properties of these polymers were compared. The results showed that all of the PBIs had good thermal stabilities.