Efficient CO2 Separation Using a PIM‐PI‐Functionalized UiO‐66 MOF Incorporated Mixed Matrix Membrane in a PIM‐PI‐1 Polymer

Abstract Metal–organic framework (MOF) incorporated mixed–matrix membranes (MMMs) attract great interest for gas separation applications because they overcome limitations faced by typical polymer membranes, including permeability–selectivity trade‐off, aging effect, and plasticization phenomenon. However, optimal MOF–polymer interface compatibility is the key challenge in fabricating defect‐free high‐performance gas‐separation MMMs. Here, a surface modification strategy of the UiO‐66‐NH 2 MOF using a covalently bound PIM‐PI‐oligomer is developed to engineer interface compatibility with the polymer that has an identical chemical structure (PIM‐PI‐1) in the MMMs. A series of MMMs are prepared with different loadings of homogeneously distributed PIM‐PI‐functionalized MOFs (PPM). Significant improvements in CO 2 /N 2 and CO 2 /CH 4 selectivity and permeability are achieved with these MMMs, ranging from 5 to 10 wt% of the PPM loadings. The MMM with 10 wt% loading (PPM‐10@MMM) shows a CO 2 permeability of 3827.3 Barrer and a CO 2 /N 2 and CO 2 /CH 4 selectivity of 24 and 13.4, respectively. This surpasses the 2008 Robeson upper bound for CO 2 /N 2 and is very close to the 2008 upper bound for CO 2 /CH 4 . The experimental results are further compared using Maxwell's equation for MMMs. The resulting MMMs show a plasticization resistance against CO 2 up to 25 atm pressure and anti‐aging performance for 180 h.