Asymmetric membrane formation via immersion precipitation method. I. Kinetic effect
Asymmetric membrane formation via immersion precipitation method. I. Kinetic effect
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DOI：
10.1016/s0376-7388(00)81536-7
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发表时间：
1991
影响因子：
9.5
通讯作者：
S. K. Yong;J. K. Hyo;Young Kim Un
中科院分区：
文献类型：
--
作者：
S. K. Yong;J. K. Hyo;Young Kim Un
的相转化过程对膜形态的动力学效应进行了探讨，强调作为衡量的溶剂/非溶剂交换速率的非溶剂的扩散系数。扩散系数与聚合物溶液的非溶剂耐受性密切相关，这是从以下系统的伪三元相图估计的：聚合物：聚砜;溶剂系统：溶剂1-甲基-2-吡咯烷酮和溶剂添加剂（甲酸、水或乙醇）的混合物;和非溶剂：乙醇。无论采用哪种溶剂添加剂，当非溶剂的扩散系数对于给定的凝胶化介质是高的时，则膜由光滑的、无缺陷的表面和无大孔的横截面组成，并且对氧是高度可渗透的。然而，使用具有低扩散系数的聚合物溶液导致相当有缺陷的形态的膜。因此，可以得出结论，非溶剂的扩散系数是控制膜形态的关键参数。
The kinetic effect of the phase inversion process on the membrane morphology is explored, with emphasis on the diffusion coefficient of the nonsolvent as a measure of the solvent/nonsolvent exchange rate. The diffusion coefficient is closely related to the nonsolvent tolerance of the polymer solution, which was estimated from a pseudo-ternary phase diagram of the following system: polymer: polysulfone; solvent system: a mixture of the solvent 1-methyl-2-pyrrolidinone and a solvent additive (formic acid, water or ethanol); and nonsolvent: ethanol. Regardless of the kind of solvent additive employed, when the diffusion coefficient of the nonsolvent is high for a given gelation medium, then the membrane consists of a smooth, defect-free surface and macrovoid-free cross section, and is highly permeable to oxygen. However, using a polymer solution with a low diffusion coefficient results in a membrane of a rather defective morphology. Therefore, it is concluded that the diffusion coefficient of the nonsolvent is a crucial parameter in controlling membrane morphology.