Hydrogen-bond-assisted thermally crosslinked PIM membranes for selective H2 and CO2 separation with enhanced plasticization resistance

Ring-opened TB-OR is blended with PIM-1 to form a hydrogen-bonded membrane. • The TB-OR-PIM treated at 350 °C for 10 h achieve CO 2 /CH 4 selectivity of 330.0. • The optimized membranes exhibit 17.4- and 34.4-fold selectivity improvements. • The membranes show excellent resistance to CO 2 plasticization at 600 psi. Polymers of intrinsic microporosity (PIM) membranes have shown great potential for hydrogen purification and carbon dioxide separation, but often suffer from low gas selectivity. Here, a hydrogen-bonded-assisted, thermally crosslinked membrane is prepared by incorporating ring-opened TB-OR with PIM-1. Hydrogen-bonding interactions between the amine groups of TB-OR and the nitrile groups of PIM-1 promote interchain association and preorganization before thermal treatment. Subsequent thermal treatment induces chain rearrangement, structural densification, and partial covalent crosslinking, while hydrogen-bonding interactions are re-established upon cooling, leading to a more size-selective microporous structure. The membrane treated at 350 °C for 10 h exhibits CO 2 /CH 4 and H 2 /CH 4 selectivities of 330.0 and 708.3, representing 17.4- and 34.4-fold improvements over the uncrosslinked membrane, surpassing the 2019 upper bound for CO 2 /CH 4 and approaching the 2015 upper bound for H 2 /CH 4 separation. Both pure- and mixed-gas tests at 600 psi confirm excellent resistance to CO 2 plasticization, while aging measurements further demonstrate improved performance stability. These results highlight the effectiveness of hydrogen-bond-assisted thermal crosslinking in regulating chain packing and microporous structure in PIM-based membranes for hydrogen purification and high-pressure CO 2 separation. A thermally crosslinked membrane platform was developed by integrating ring-opened TB-OR with PIM-1 to simultaneously enhance gas separation selectivity and operational stability. Download: Download high-res image (388KB) Download: Download full-size image