Preparation and Properties of PEEK-g-PAA Separation Membranes with Extraordinary Solvent Resistance for Emulsion and Organic Liquid Separation

Materials with remarkable chemical durability and benign separation capacity synchronously have recently attracted extensive interest for diverse purification application. Herein, a poly(ether ether ketone) (PEEK) porous membrane with excellent solvent resistance and corrosion resistance was successfully prepared by the combination of non-solvent induced phase separation (NIPS) and acid treatment. Meanwhile, for the first time, a hydrophilic poly(acrylic acid) (PAA) polymer was in situ grafted on the surface of the PEEK separation membrane by the ultraviolet grafting method, improving the membrane interface, and the membrane surface water contact angle declined from 89.31° to 20.21°. The solvent-resistant PEEK-g-PAA-2 separation membranes (the PAA-grafted membranes with best performance) could separate oil-bearing systems with high efficiency above 99.0%. Furthermore, the PAA layer endowed PEEK-g-PAA membranes with anti-fouling capacity. Benefited from the extraordinary solvent resistance of the PEEK-g-PAA-2 membranes, after immersion in chloroform for 6 h, the membranes maintained the intact morphology, exhibiting far more extraordinary solvent-resistance than commercial poly(vinylidene difluoride) (PVDF) and poly(phenylene sulfone) (PPSU) membranes. In conclusion, the PEEK-g-PAA-2 membranes could be applied in the separation of more types of oil–water and oil–oil mixtures, solving the problem that the universally reported polymer membranes have certain solubility in solvents. These features reveal the appealing development potential of the PEEK-based membranes to be utilized in the emulsion separation and organic liquid separation field.