(317h) New Approach to Improve Gas Permeability through Amorphous Glassy Polymer Membranes

All polymeric membranes have permeable and selective properties to gas molecules, as revealed by pioneers like Graham. In the field of membrane-based gas separation, it is no doubt that an ultimate goal is to develop ideal materials having high permeability and selectivity for gas mixtures such as H2/CO2, O2/N2, CO2/N2 and CO2/CH4. From many efforts, advanced polymeric materials and epoch-making membrane formation methods have emerged and put the spurs to more realization of membrane-based gas separation. However, seemingly, the performance of polymeric membranes for gas separation will be rarely or slowly improved even in the future. This prospect, unfortunately, arises from a common belief based on database of previous studies and theoretical backgrounds. In this study, a special attention was paid to high performance homopolymers and copolymers possessing excellent thermal and chemical stability, partially rigid rod structure, and high free volume. So we designed three kinds of functionalized polyimides. These polymers have functionalized hydroxyl, amino, thiazol groups and easily made from two-step thermal imidization process. These polymers were thermally converted to polybenzoxazole, polyimidazopyrrolone, polybenzthiazole by heating the films. There gas separation performance was confirmed by molecular probe study with time-lag method.