Hyper cross‐linked polymers containing amino group functionalized polyimide mixed matrix membranes for gas separation

Abstract The design and synthesis of porous materials with novel structures and functional groups to prepare mixed matrix membranes (MMMs) is an effective way to break through trade‐off effect of membrane technology. Here, hyper cross‐linked polymers containing amino groups (HCPs‐NH 2 ) with philic‐CO 2 frame were successfully prepared for the fabrication of polyimide (PI)/HCPs‐NH 2 MMMs. The separation performance of pure gas is studied in order to explore NH 2 groups facilitating CO 2 diffusion and transmission and enhancing CO 2 permeability. Consequently, the permeability of the PI/HCPs‐NH 2 MMMs toward CO 2 and O 2 are 77.56 Barrer and 17.91 Barrer versus pure PI film toward CO 2 and O 2 (62.42 Barrer and 13.85 Barrer). The selectivity for CO 2 /CH 4 and O 2 /N 2 pairs is 24.44 and 4.01, and the selectivity of pure PI film toward CO 2 /CH 4 and O 2 /N 2 pairs is 20.76 and 3.29, respectively. The permeability and selectivity of PI/HCPs‐NH 2 MMMs are higher than pure PI film breaking through the trade‐off effect. Moreover, the PI/HCPs‐NH 2 MMMs show better separation performance on the CO 2 /CH 4 pair than the O 2 /N 2 pair, indicating HCPs‐NH 2 with philic‐CO 2 frame plays a very important role in promoting CO 2 permeability. Thus, the PI/HCPs‐NH 2 MMMs have potential applications in the field of natural gas purification.