Development of High Performance Pyrolized Polyimide‐based Carbon Molecular Sieves for Enhanced Selectivity of Propylene/Propane Gas Separation

selectivity of 66. Notably, after an extended period of continuous mixed-gas testing and aging at 4 bar over 147 days, the CMS membrane exhibited a remarkable increase in mixed-gas propylene/propane selectivity to 152-an unmatched value to date for a CMS material-because of selective tightening of the CMS microstructure by physical aging.