Hydrophilic Modification of PPSU Membranes Using PANCMA Polymers

Polypropylene sulfone (PPSU) films were prepared by non-solvent-induced phase separation. Acrylonitrile maleic anhydride (PANCMA) polymers were first prepared by aqueous phase polymerization, which were characterized by FT-IR and X-ray diffraction (XRD). PANCMA (0%, 0.5%, 1%, 2%, 3%(wt)) were used to modify PPSU films using its carboxyl functional groups. Effects of PANCMA on microstructure, hydrophilicity, flux, molecular weight cut off, BSA static adsorption capacity and retention rate of methyl blue dye of the film were investigated. SEM results show that with the increase of PANCMA content, finger like structure gradually decreases and the thickness of the film increases. Moreover, pure water flux of the PPSU/PANCMA composite membrane decrease from 59.3 L·m^-2·h^-1 to 10.8 L·m^-2·h^-1, and the molecular weight cut off decreases from 17,500 Da to 4,400 Da. The contact angle of the film decreases from 78° to 38°. PANCMA improves hydrophilicity of PPSU films and the best performance is found when PANCMA content is 2%(wt). BSA static adsorption capacity is nearly 20 times lower than that of the original membrane and pollution resistance is improved. The prepared membrane is used to treat methyl blue solution, and the rejection rate increases from 54% to 89%, which indicates that the rejection performance of the modified membrane is improved.