掺杂两亲性嵌段共聚物构筑抗污染自清洁聚醚砜膜

Endowing the Antifouling and Self-cleaning Properties of Poly(ether sulfone)Oil/Water Separation Membrane by Blending with Amphiphilic Block Copolymer Additive

通过可逆加成-断裂链转移聚合(RAFT)制备嵌段共聚物聚乙二醇单甲醚-b-聚甲基丙烯酸六氟丁酯-b-聚甲基丙烯酸缩水甘油酯(mPEG-b-PHFBM-b-PGMA).将其作为改性剂,通过非溶剂诱导相分离法制备聚醚砜(PES)/mPEG-b-PHFBM-b-PGMA复合膜.在成膜过程中亲水性的聚乙二醇链段发生自由表面偏析的同时,带动低表面能的PHFBM链段发生强制表面偏析,进而构建抗污染、自清洁的膜表面.PES/PFG5复合膜的纯水通量和油水通量分别为290.25和252.89 L·m^(-2)·h^(-1),而未改性的PES膜分别只有64.10和11.09 L·m^(-2)·h^(-1).相对于PES空白膜,通量恢复率从45.75%提高至90.15%,油水通量衰减率由82.70%降至12.87%,抗油污染能力大幅度增强.由于mPEG-b-PHFBM-b-PGMA中的PGMA链段与PES链段之间的物理缠结以及疏水作用力,其在PES膜中表现出良好的稳定性,表明该膜材料在油水分离中具有良好的应用前景.

Oil/water separation is a worldwide challenge because large amounts of oily wastewater are produced in our daily life and many industrial processes.There is a growing tendency to employ ultrafiltration membrane for treating oily wastewater due to its low energy consumption,high operation efficiency and environmentally friendly characteristic.Recently,amphiphilic copolymers were designed as additives to fabricate composite membranes through physical blending modification,which has quickly become a research hotspot due to its simple operation.In this work,a novel amphiphilic block copolymer of poly(ethylene glycol methyl ether)block poly(hexafluorobutyl methacrylate)block poly(glycidyl methacrylate)(mPEG-b-PHFBM-b-PGMA)was beforehand synthesized via reversible addition-fragmentation chain transfer polymerization(RAFT).Then,the PES/mPEG-b-PHFBM-b-PGMA composite membrane was prepared by the NIPS method.In the membrane formation process,the hydrophobic PGMA segments in mPEG-b-PHFBM-b-PGMA act as an anchor,which amalgamated with hydrophobic PES molecular.At the same time,the hydrophilic mPEG segments migrated spontaneously to the membrane surface via a“free surface segregation”approach,dragging the low surface energy PHFBM segments onto membrane surfaces.In this way,an antifouling and self-cleaning advanced membrane surface was constructed.The pure water flux and oil flux of the PES/PFG5 composite membrane are around 290.25 and 252.89 L·m^(−2)·h^(−1),respectively.The corresponding values of the PES blank membrane are only 64.10 and 11.09 L·m^(−2)·h^(−1),respectively.Compared with the unmodified PES membrane,the flux recovery ratio increases from 45.75%to 90.15%,while the permeation flux-decline value decreases from 82.70%to 12.87%,suggesting the excellent anti-fouling and self-cleaning property of the modified PES/PFG5 composite membrane.Furthermore,the mPEG-b-PHFBM-b-PGMA copolymer exhibits good stability due to the physical intertwisting and hydrophobic interaction between the PGMA and PES,suggesting the good application prospect of the membrane in oil/water separation.