Water Vapor Sorption, Diffusion, and Dilation in Polybenzimidazoles

• DOI: 10.1021/acs.macromol.8b01659
• Publication Date: 2018-09-10T10:42:11Z
• Authors: Joshua D. Moon; Michele Galizia; Hailun Borjigin; Ran Liu; Judy S. Riffle; Benny D. Freeman; Donald R. Paul
• Keywords: 02 engineering and technology; 0210 nano-technology

Polybenzimidazoles (PBIs) have been investigated for use as gas separation membranes due to their thermal stability and good H2/CO2 performance at elevated temperatures. However, PBIs are hydrophilic, effects of water vapor on PBI essentially unexplored. This study investigates sorption, diffusion, dilation a commercial PBI, Celazole, recently synthesized sulfonyl-containing TADPS-TPA. Water binds strongly both polymers requires temperatures removal. sorption in Celazole follows dual-mode behavior up unit activity, while upward concavity is observed high activities the TADPS-TPA isotherm. Both swell significantly water, desorption hysteresis suggests water-induced conditioning matrix. Model fits enable estimation partial molar volume water-accessible fractional free (FFV) function activity. diffusion coefficients increase with increasing which correlates FFV.