Abstract:Polyimide is a kind of high-performance polymer containing imide ring formed from dianhydride and diamine monomer through polycondensation reaction. It has the characteristics of high thermal stability, high mechanical properties, structural diversity, good film-forming properties and shows good gas separation performance. However, the gas separation is still limited by Roberson upper bound. This article reviewed preparation of polyimide and membranes and the modification methods of polyimide gas separation membranes, briefly described current core problems of polyimide gas separation membranes, including physical blending, cross-linking modification, molecular structure design, preparation of thermally rearranged polymers and carbon molecular sieve membranes, and focused on reviewing the research progress of polyimide gas separation membrane modification. The article pointed out that with the continuous improvement of performance requirements of polyimide gas separation membranes in industry, developing new polyimide membrane materials, optimizing properties of polyimide membrane materials, and simplifying preparation and modification methods of polyimide gas separation membranes have become the focus of future research on polyimide gas separation membranes.