Hydrogen-bond crosslinking of Trӧger's base polymer membranes for enhanced gas selectivity and plasticization resistance
Yongchao Sun, Zeyuan Gao, Lu Bai, Tianyou Li, Fangxu Fan, Fake Sun, Yijun Liu, Jianyu Guan, Gaohong He, Canghai Ma
Abstract
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.