Copolyimide gas separation membranes derived from substituted methylene dianilines and unsubstituted diamines.

摘要

Semiflexible aromatic polyimides for preparing gas separation membranes and the process of using to separate at least one gas from a mixture of gases is disclosed. The aromatic polyimides are prepared by polycondensation of aromatic tetracarboxylic dianhydrides with 20 to 80 mol percent of a methylene dianiline which is alkyl substituted on all positions ortho to the amine functions. The remaining diamine constituent is not so substituted.