摘要
以聚醚砜（ＰＥＳ）为膜材料，ＤＭＡｃ为溶剂，研究了３种非溶剂添加剂（ＮＳＡ）———ＥｇＯＨ、ＤｅｇＯＨ和ＢｕＯＨ在水和ＮＳＡ中凝胶对平板微孔膜性能的影响．利用浊点法得到ＰＥＳ／ＤＭＡｃ／ＮＳＡ和ＰＥＳ／ＤＭＡｃ／ＮＳＡ／Ｈ２Ｏ体系２５℃的相图；并以邻近比α值来表征膜溶液组成点靠近相分离的程度．添加了ＮＳＡ的铸膜液在水中凝胶制备微孔膜，以ＥｇＯＨ为非溶剂添加物，在相同聚合物浓度、相同凝胶条件下，仅仅改变铸膜液的邻近比可以获得成倍透量差别的微孔膜；随α的增加，膜结构从指状孔结构变化到海绵结构．结果表明，ＮＳＡ的影响不是以量来表征的，而是受控于溶液的邻近比α．铸膜液组成邻近浊点曲线，发生快速相分离有利于制备高透量的微孔膜．以ＤｅｇＯＨ为ＮＳＡ，当铸膜液α值高时，可以获得高透量的微孔膜．考察不同ＮＳＡ作凝胶剂对膜性能的影响，发现微孔膜的透量不仅取决于膜孔的大小，也决定于膜孔之间的相互连通性．膜孔之间的相互连通性是由凝胶相转化过程中溶剂的溢出速率和膜结构固化前铸膜液剩余溶剂含量决定的．
Flat-type poly(ether sulfone)(PES)membranes for microfiltration were prepared by the traditional phase-inversion technique in water and organic nonsolvent.The effects of three kinds of nonsolvent additives(NSA),ethyl glycol(EgOH),diethyl glycol(DegOH) and n-butanol(BuOH)with difference in polarity and solvating power on the membrane performance were examined in terms of water flux and maximum pore size.The compatibility of the three NSA with PES/DMAc were investigated in terms of cloud point for systems of PES/DMAc/NSA and PES/DMAc/NSA/H2O.With the ratio of near-to-cloud-point,α,it found that,with the same NSA,polymer concentration and coagulation conditions,the increase of α value could lead to the changing of membrane structure from finger to sponge and a remarkable increase of water flux when α is larger than 0.55.Moreover,high flux MF membranes could be obtained without apparently increase of the pore size.It is suggested that the water flux be related not only to the pore size but also the connectivity among the pores in the top layer of the membranes.Furthermore.the solvent content just before the membrane structure solidify and the outflow rate of the solvent during phase inversion process were two important factors controlling the connectivity of pores.
出处
《膜科学与技术》
CAS
CSCD
1998年第3期43-48,共6页
Membrane Science and Technology
关键词
聚醚砜
微孔膜
非溶剂添加剂
膜分离
poly(ether sulfone) microfiltration membrane nonsolvent additive
