| abstract |
A carbon molecular sieve (CMS) membrane is made by pyrolyzing a film or hollow fiber membrane made of a polyimide polymer or copolymer essentially consisting of repeating units of dianhydride-derived units and diamine-derived units. At least 50% of the dianhydride-derived units are derived from 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane (6FDA). At least 50% of the diamine-derived units are derived from 2,5-diethyl-6-methyl-1,3-diamino benzene (DETDA). |