PVP对PESU中空纤维膜的结构调控

Structural Regulation of Polyethersulfone Hollow Fiber Membrane by PVP

以聚醚砜(PESU)为膜材料,聚乙烯吡咯烷酮(PVP)为添加剂,N,N-二甲基乙酰胺(DMAc)为溶剂,用非溶剂致相分离法制备了中空纤维膜。采用哈克旋转流变仪测定了两种分子量的PVP(PVP-K60,PVP-K90)在不同混配比下PESU纺丝溶液的流动曲线,并对所得膜丝进行了形貌结构、亲水及分离性能表征。结果表明,添加单一PVP体系膜中,添加PVP-K60的膜外表面平均孔径及开孔率较大;PVP-K90/PVP-K60共混膜的外表面平均孔径与开孔率均不低于纯PVP-K90所得膜,其中共混比为4/1的膜外表面平均孔径则高于纯PVP-K60所得膜;共混比为2/3的中空纤维膜为全海绵状结构且含水量较高;添加单一PVP-K60的膜纯水通量达171.6 L/(m^(2)·h),所有膜的牛血清蛋白(BSA)截留率均超过98%。不同分子量的PVP共混能实现对膜丝结构的调控及对性能的改善,且对结构与性能产生协同作用的混配比不同。

The hollow fiber membrane was prepared by non-solvent phase separation with Polyethersulfone(PESU)as the membrane material,Polyvinylpyrrolidone(PVP)as an additive,and N,N-dimethylacetamide(DMAc)as the solvent.The viscosity vs.shear rate sweep curve of PESU spinning solutions with various mixing ratios of PVP containing two molecular weights(PVP-K60,PVP-K90)were measured by Haake rotary rheometer.The structure of the membrane was characterized by Scanning electron microscopy(SEM)and the hydrophilic and separation properties of the obtained membrane was studied by water content and flux test.The results show that the average pore size and porosity of the outer surface of the PVP-K60 membrane in a single PVP system membrane are larger;the average pore size and surface porosity of the PVP-K90/PVP-K60 blend membrane are not lower than those of the pure PVP-K90 membrane,and the average pore diameter of the outer surface of the membrane with a blend ratio of 4/1 is higher than that of the pure PVP-K60 membrane;the hollow fiber membrane with a blend ratio of 2/3 present a full sponge-like structure and has a high water content;the pure water flux of a single PVP-K60 membrane reaches 171.6 L·m^(-2)·h^(-1),and the bovine serum albumin(BSA)rejection reaches more than 98%for all membranes.The blending of PVP with different molecular weights can tailor the structure of hollow fiber membrane and improve their properties,and synergy effect produced by different blending ratios of PVP-K90/PVP-K60 for structure and performance is different.