ABSTRACT
Abstract Polybenzimidazoles (PBIs) represent a unique class of polymers with exceptional thermo-mechanical properties and chemical resistance suitable for a variety of applications ranging from flame-resistant fabrics to aerospace materials. While the commercial applications of the high temperature, high performance thermoplastic PBI, both as fibers and as molded materials with the trade name of Celazole®, are well-documented, this review seeks to emphasize the synthesis, processing, properties and potential applications of the rigidrod version known as polybenzobisimidazoles. Various rigid-rod PBI-based molecular motifs for proven as well as potential enhancement in the axial compressive properties of rigid-rod polymeric fibers are described. In many instances, corresponding polybenzobisthiazole (PBZT) and polybenzobisoxazole (PBO) rigid-rod polymer structures are also discussed, for comparison. Rigid-rod polybenzobisimidazoles with sulfonic acid pendants and their novel solubilization and processability as rod-like reinforcement in molecular composites is also described. Derivatized rigid-rod polybenzobisimidazoles with alkylsulfonate pendants are also discussed from the viewpoint of their high ionic conductivities for potential utilization in such areas as polyelectrolytes for rechargeable battery applications.
