Synthesis and characterization of thermally stable polymers containing phenazine

The synthesis and characterization of two thermally stable polymers containing a polybenzimidazole and a ladder polymer structure are described. The tetraamino derivative of phenazine required for these syntheses was obtained by the reduction of the commercially available diamino, dinitro derivative of benzene. The polybenzimidazole polymer was synthesized by condensing tetraaminophenzine with terephthaldehyde in dimethylacetamide solvent. The resulting polymer had an intrinsic viscosity of 0.94 g/dl in methanesulfonic acid solvent. The TGA of the polymer showed it to be stable up to 470°C. The ladder polymer was prepared by reacting tetramainophenazine with dihydroquinone in polyphosphoric acid at a temperature of 146°C. The polymer formed a brittle, free-hanging film when cast from methanesulfonic acid. The molecule exhibited high degree of crystallinity and had a tendency to form dendritic-shaped structures. Doping with 15% iodine resulted in a conductivity of 9×10−7 mho/cm. It was thermally stable in air, showing a 10% weight loss at 410°C.