Novel PVDF- g-NMA Copolymer for Fabricating the Hydrophilic Ultrafiltration Membrane with Good Antifouling Property

Improving the hydrophilicity of the poly(vinylidene fluoride) (PVDF) ultrafiltration membrane can change its adsorption fouling characteristics. Here, a novel amphiphilic material of PVDF grafted with N-methylolacrylamide (PVDF-g-NMA) was developed via photoinduced Cu(II)-mediated reversible deactivation radical polymerization (RDRP). The PVDF-g-NMA ultrafiltration membrane was prepared by the nonsolvent-induced phase-separation method. The PVDF-g-NMA copolymer was characterized by 1H NMR and Fourier transform infrared spectroscopy. The performance of the PVDF-g-NMA membrane was evaluated by determining the permeation flux, contact angle, roughness, and antifouling tests. The roughness data show that a low content of N-methylolacrylamide can effectively reduce the surface roughness of membranes by 50%, resulting in greater antifouling ability. The prepared ultrafiltration membrane containing 15 wt % PVDF-g-NMA exhibited the best hydrophilicity with an average pure water flux of up to 272.1 L·m-2·h-1, higher than that of the pure PVDF membrane (45.4 L·m-2·h-1). The contact angle of the PVDF-g-NMA ultrafiltration membrane decreased from 85.5 to 67.4°. The bovine serum albumin rejection rate of the PVDF-g-NMA membrane significantly increased from 85.7 to 92.6%, and the pure water flux recovery rate increased from 79.0 to 88.5%. The PVDF-g-NMA ultrafiltration membrane had excellent hydrophilicity and antifouling properties, which would be promising for wastewater treatment.