Polyimides with excellent physicochemical properties have aroused a great deal of interest as gas separation membranes; however, the severe performance decay due to CO2-induced plasticization remains a challenge. Fortunately, in recent years, advanced plasticization-resistant membranes of great commercial and environmental relevance have been developed. In this review, we investigate the mechanism of plasticization due to CO2 permeation, introduce effective methods to suppress CO2-induced plasticization, propose evaluation criteria to assess the reduced plasticization performance, and clarify typical methods used for designing anti-plasticization membranes.

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A great deal of fossil fuel is consumed due to enormous industrial and domestic activities. Meanwhile, massive emissions of CO2 have led to global warming. Replacing coal with natural gas will greatly decrease CO2 emissions. However, this requires cutting‐edge technologies to purify CH4. Polymeric membranes with both high permeability and high selectivity are preferred but there exists a trade‐off between them. To solve the problem, we incorporated the UiO‐66 and UiO‐66‐NH2 metal organic frameworks (MOFs) nanoparticles into a Tröger's base polymer, dimethylbiphenyl Tröger's base polymer (DMBPTB). The CO2 permeability of the UiO‐66/DMBPTB nanocomposite membranes increased by 13 folds with a marginal decrease in selectivity. Moreover, the composite membranes with amine‐functionalized UiO‐66 nanoparticles showed higher permeability and selectivity to the CO2/CH4 gas pair. The best gas separation performance was obtained for the composite membrane having 30 wt% UiO‐66‐NH2 nanoparticle, where the selectivity of CO2/CH4 was 18.0, and the CO2 permeability was 744 Barrer.