PVDF ultrafiltration membranes of controlled performance via blending PVDF-g-PEGMA copolymer synthesized under different reaction times

• Published in: Frontiers of environmental science & engineering 2018-04, Vol.12 (2), p.29-40, Article 3
• Main Authors: Wang, Shuai, Li, Tong, Chen, Chen, Liu, Baicang, Crittenden, John C.
• Format: Article
• Language: English
• Subjects: Additives; Amphiphilic copolymer; Atomic transfer radical polymerization; Blended modification; Chemical synthesis; Copolymers; Earth and Environmental Science; Environment; Graft copolymers; High flux; Membranes; Mixtures; Oxygen content; Phase inversion; Phase shift; Polyethylene glycol; Polyvinylidene fluoride ultrafiltration membrane; Polyvinylidene fluorides; Pore size; Pore size distribution; Reaction time; Research Article; Segments; Size distribution; Ultrafiltration; Viscosity; 混合添加剂; 反应时间; PVDF; 膜性能; 共聚物; 控制性能; 孔尺寸分布; 水流动
• ISSN: 2095-2201; 2095-221X
• DOI: 10.1007/s11783-017-0980-0

Polyvinylidene fluoride grafted with poly（ethylene glycol） methyl ether methacrylate （PVDF-g- PEGMA） was synthesized using atomic transfer radical polymerization （ATRP） at different reaction times （9 h, 19 h, and 29 h）. The corresponding conversion rates were 10%, 20% and 30%, respectively. PVDF was blended with the copolymer mixtnre containing PVDF-g-PEGMA, solvent and residual PEGMA under different reaction times. In this study, we explored the effect of the copolymer mixture additives with different synthesis times on cast membrane performance. Increasing the reaction time of PVDF-g-PEGMA causes more PVDF-g-PEGMA and less residual PEGMA to be found in the casting solution. Incremental PVDF-g-PEGMA can dramatically increase the viscosity of the casting solution. An overly high viscosity led to a delayed phase inversion, thus hindering PEGMA segments in PVDF- g-PEGMA from migrating to the membrane surface. However, more residual PEGMA contributed to helping rnore PEGMA segments migrate to the membrane surface. The pure water fluxes of the blended membrane with reaction times of 9 h, 19 h, and 29 h are 5445 L. m 2.h I 1068 L- m 2.h land 1179 L.m 2.h I respectively, at 0.07 MPa. Delayed phase inversion can form smaller surface pore size distributions, thus decreasing the water flux for the membranes with PVDF-g-PEGMA at 19 h and 29 h. Therefore, we can control the membrane pore size distribution by decreasing the reaction time of PVDF-g-PEGMA to obtain a better flux performance. The membrane with PVDF-g-PEGMA at 19 h exhibits the best foulant rejection and cleaning recovery due to its narrow pore size distribution and high surface oxygen content.