Hydrogen bonding-induced 6FDA-DABA/TB polymer blends for high performance gas separation membranes

To promote polyimide gas transport properties, we propose a facile technique through adjustable hydrogen bonding energy through blending polyimide (6FDA-DABA) containing -COOH groups and Troger's base (TB) polymer without damaging polymer chemical structures. The hydrogen bonding strength between -OH groups in PI and the N atoms in TB (O-H center dot center dot center dot N) is well tailored via controlled thermal treatment which has been confirmed by molecular simulations. Hydrogen bonding amounts and strength reach maximum within membranes annealed at 120 degrees C for 16 h, and exhibit CO2/CH4 and H-2/CH4 selectivities of 115.0 and 481.8 respectively, surpassing the 2008 upper bound. Contributed by the enhanced hydrogen bonding strength, the membranes annealed at 120 degrees C for 16 h display excellent CO2 plasticization resistance and physical aging in comparison with pristine PI and TB membranes. Such a approach potentially renders a synthetic membrane applicable for CO2 separation and hydrogen purification at high temperatures.