Solvent-induced microphase separation membranes of block poly (aryl ether sulfone) copolymer with high selectivity of O2/N2 separation

Gas separation membranes have a wide range of applications in industry, and there are two important factors in judging membrane standards permeability and selectivity. How to improve the selectivity of gas separation membranes while improving permeability is a challenge. In this study, poly (aryl ether sulfone) (PES) block copolymers were synthesized from fluorine-terminated polysulfone (PSF–F) and hydroxyl-terminated cardo PES containing phenyl substituted isoindolinone side group (PES-PPI-OH). Large side groups can enlarge the free volume and hinder chain movement to improve gas permeation behavior. Solvent-induced microphase separation of block copolymers by casting membranes with solvent benzyl alcohol (BA) can improve selectivity. The PSF-b-PES-PPI (10:10) BA membrane maintain good mechanical properties and tensile strength up to 93 MPa which compared to random polymer membrane rises to 14 MPa. Gas permeation at 23 °C showed that the O2/N2 selectivity of PSF-b-PES-PPI (5:15)BA membrane was 10.6, which was the 2008 Robeson upper bound. Thus, poly (aryl ether sulfone) materials showed great potential application for O2/N2 separation.