Gas transport properties of new aromatic polyimides based on 3,8-diphenylpyrene-1,2,6,7-tetracarboxylic dianhydride

摘要

Three novel polyimides have been successfully synthesized from 3,8-diphenylpyrene-1,2,6,7-tetracarboxylic dianhydride (DPPD), and three commercial diamines by solution polycondensation. All polymers exhibited high molecular weight, high thermal stability and high rigidity (no glass transition was detected up to 400°C) and free volume. The new polymers have been tested as gas separation membranes, showing very good combination of permeability and selectivity, especially in the case of the polymer derived from trimethyl-m-phenylenediamine (TMPD), which overpassed the 1991 Robeson upper bound for the gas pairs O2/N2 and CO2/CH4 and was near the 2008 upper bound for CO2/N2.