On the formation of macrovoids in PMMA membranes

被引:45
作者
Lai, JY
Lin, FC
Wu, TT
Wang, DM [1 ]
机构
[1] Natl Taiwan Univ, Dept Chem Engn, Taipei 10617, Taiwan
[2] Chung Yuan Christian Univ, Dept Chem Engn, Membrane Res Lab, Chungli 32023, Taiwan
关键词
membrane preparation; membrane structure; macrovoid; formation mechanism;
D O I
10.1016/S0376-7388(98)00292-0
中图分类号
TQ [化学工业];
学科分类号
0817 ;
摘要
In this work, the formation of macrovoids in two membrane formation systems was investigated. The polymer and the coagulant used in these two systems were the same: PMMA and water, but the solvents used to dissolve PMMA were different-NMP for one system (system A) and acetone/Tween 80 solution for the other (system B). According to SEM and AFM analyses, it was found that, although the macrostructures of the membranes fabricated by systems A and B are similar, the microstructures are different. On the basis of optical observation of the growth of macrovoids, it is proposed that the difference in the microstructure can be explained by the difference in the growth mechanism of macrovoids: the growth of macrovoids is by convection for system A and by diffusion for system B. The difference in the growth mechanism of macrovoids can also account for some other differences between systems A and B: system B is more sensitive to the casting thickness than system Al and the addition of salt in the coagulation bath can effectively inhibit the growth of macrovoids in system B but not in system A. (C) 1999 Elsevier Science B.V. All rights reserved.
引用
收藏
页码:31 / 43
页数:13
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