Gas separation properties of systems with different amounts of long poly(ethylene oxide) segments for mixtures including carbon dioxide

► Copoly(ether-imide) membranes (BKDA, ODA and PEO-6000) were manufactured and tested. ► The membranes have good mechanical properties with very good CO2 permeabilities. ► Gas permeability increased with amorphous PEO% and with treatment and operation T. ► CO2/N2 permselectivities were close their theoretical upper bound especially for 50 °C.