Hydrogen-bond crosslinking of Trӧger's base polymer membranes for enhanced gas selectivity and plasticization resistance

Membrane technology holds the potential to significantly improve energy-efficient industrial processes, fostering a more sustainable green economy. However, overcoming the challenges of gas permeability-selectivity tradeoffs and CO 2 induced plasticization in gas separation materials remains a critical focus. This study presents a functionalization method for Trӧger's base (TB) based polymers by modifying them with phosphoric acid to create hydrogen bonds within the membrane structure. This approach enables ultra-high gas selectivity for multiple gas pairs, including H 2 /CH 4 , H 2 /N 2 , and O 2 /N 2 . The crosslinked membranes display H 2 and O 2 permeability of 248.0 and 27.9 Barrer, respectively, with H 2 /CH 4 , H 2 /N 2 , and O 2 /N 2 selectivity of 202.1, 115.7 and 10.0, respectively, exceeding the 2008 Robeson upper bounds for these gas pairs. Moreover, the crosslinked membranes demonstrate excellent anti-plasticization properties, withstanding pressures up to 600 psi in high-pressure CO 2 feed tests. These results suggest that the hydrogen bonds formed between the TB polymer and phosphoric acid in the membranes effectively mitigate polymer chain swelling. This design approach presents a promising pathway to developing membrane materials with enhanced performance for energy-efficient gas separation processes.