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This study reports 6FDA:BPDA-DAM polyimidederived hollowf iber carbon molecular-sieve (CMS) membranes for hydrogen and ethylene separation. Since H 2 /C 2 H 4 selectivity is the lowest among H 2 /(C 1 -C 3 )h ydrocarbons,a n optimizedC MS fiber for this gas pair is useful for removing hydrogen from all-cracked gas mixtures.Aprocess we term hyperaging provides highly selective CMS fiber membranes by tuning CMS ultramicropores to favor H 2 over larger molecules to give aH 2 /C 2 H 4 selectivity of over 250. Hyperaging conditions and ah yperaging mechanism are discussed in terms of an expedited physical aging process,w hich is largely controlled by the hyperaging temperature.F or the specific CMS material considered here,ahyperaging temperature beyond 90 8 8Cbut less than 250 8 8Cworks best. Hyperaging also stabilizes CMS materials against physical aging and stabilizes the performance of H 2 separation over extended periods.This work opens ad oor in the development of CMS materials for the separation of small molecules from large molecules.

This study reports 6FDA:BPDA‐DAM polyimide‐derived hollow fiber carbon molecular‐sieve (CMS) membranes for hydrogen and ethylene separation. Since H2/C2H4 selectivity is the lowest among H2/(C1‐C3) hydrocarbons, an optimized CMS fiber for this gas pair is useful for removing hydrogen from all‐cracked gas mixtures. A process we term hyperaging provides highly selective CMS fiber membranes by tuning CMS ultramicropores to favor H2 over larger molecules to give a H2/C2H4 selectivity of over 250. Hyperaging conditions and a hyperaging mechanism are discussed in terms of an expedited physical aging process, which is largely controlled by the hyperaging temperature. For the specific CMS material considered here, a hyperaging temperature beyond 90 °C but less than 250 °C works best. Hyperaging also stabilizes CMS materials against physical aging and stabilizes the performance of H2 separation over extended periods. This work opens a door in the development of CMS materials for the separation of small molecules from large molecules.

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