The effect of molecular structure on the permeabilities of polymides

Two new polymides with aliphatic group were synthesized. The aims are to break through the limit which aromatic polyimide is primarily material as gas separation membrane in polyimide membrane materials, and to look for gas separation membrane materials with good permeability and selectivity. Meantime, the gas permeate behavior of the new polyimides was also discussed. The relationship between permeation and structure of membranes were discussed. A preliminary probe into the mechanism of CO₂ and CH₄ permeating through polyimide membrane was done.