Synthesis and Characterization of Polybenzimidazoles derived from 1 Tetraaminodiphenylsulfone for High Temperature Gas Separation Membranes

2 A series of polybenzimidazoles containing sulfonyl groups were synthesized in 3 Eaton’s reagent for high temperature H2/CO2 separation membranes. The key 4 monomer, 3,3’,4,4’-tetraaminodiphenylsulfone, was prepared via a novel and 5 economical synthetic route starting from 4,4’-dichlorodiphenylsulfone. These 6 polybenzimidazoles with sulfonyl moieties had enhanced solubilities in dipolar 7 aprotic solvents relative to the commercial Celazole ® that is prepared from 8 diaminobenzidine. Thermal gravimetric analysis showed that the materials were stable 9 at elevated temperatures with 5% weight loss values of at least 485 o C in either air or 10 N2. Glass transition temperatures of three polybenzimidazoles in this series were 11 ascertained by dynamic mechanical analysis to be 438-480 o C. These sulfonyl12 containing polybenzimidazoles exhibited excellent gas separation properties for 13 H2/CO2. Polymers from tetraaminodiphenylsulfone and either terephthalic or 14 isophthalic acid crossed Robeson’s upper bound for H2/CO2. 15