Carbazole-Based Polyimide Membranes with Hydrogen-Bonding Interactions for Gas Separation

• DOI: 10.1021/acs.macromol.4c00255
• Publication Date: 2024-06-08T13:18:11Z
• Authors: Yuyang Xiao; Xingfeng Lei; Zixiang Zhang; Siyu Chen; Guo Xiong; Xiaohua Ma; Qiuyu Zhang
• Keywords: Carbazole

Cross-linked polymers for gas separation have significant advantages in increasing selectivity and stability. However, the cross-linking strategies unavoidably form permanent interchain covalent bonds alter polymer packing state, which largely decrease solubility, static toughness, reprocessability. Herein, a secondary-amine-containing diamine (HCBDA) derived from carbazole is synthesized polymerized with 6FDA to furnish gas-permeable polyimide (HCB-PI) pseudo-cross-linked hydrogen-bonding network strengthened charge-transfer complex (CTC) effect. Compared free sample (CB-PI), HCB-PI displays more homogeneous micropore distribution denser chain packing, as proven by positron annihilation lifetime spectroscopy, results enhanced O2/N2 CO2/CH4 pairs antiplasticization property. Owing stronger interaction between skeleton molecular oxygen thus competitive adsorption mechanism, exhibits mixed-gas measurements (7.54) than pure-gas (6.58), overall property approaching 2008 Robeson upper bound. Additionally, heat-resistant mechanically robust, exhibiting toughness up 108 MJ·m–3. Our designing concept has been demonstrated be efficacious enrichment air.