Phenolphthalein polyethersulfone bearing carboxyl groups: Synthesis and its separation-membrane applications
A series of phenolphthalein polyethersulfones, containing varying contents of carboxyl groups, were synthesized via SN2 nucleophilic reaction. Structure of the prepared copolymers was confirmed by 1H NMR and FTIR. The phenolphthalein polyethersulfone comprising carboxyl groups exhibited excellent hydrophilicity and mechanical properties in the fabrication of ultrafiltration membrane. The properties of the membrane were measured using scanning electron microscopy and ultrafiltration membrane evaluator. The membrane showed superior ultrafiltration performance with a pure water flux of 399 (L·m−2·h−1), which was 1.9 times higher than that of the pristine phenolphthalein polyethersulfone. The pure water flux of the membrane with the pore-forming agent Tween 80 was up to 1082 (L·m−2·h−1), and its BSA rejection was up to 97% at 0.1 MPa. This work provided a new resin material with better performance for water treatment membrane.