Asymmetric membrane formation via immersion precipitation method. I. Kinetic effect
| Autor: | Soo Kang Yong, Young Kim Un, Jin Kim Hyo |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
chemistry.chemical_classification
Chromatography Formic acid Diffusion Filtration and Separation Polymer Biochemistry Solvent chemistry.chemical_compound Membrane chemistry Chemical engineering General Materials Science Polysulfone Physical and Theoretical Chemistry Solvent effects Phase inversion (chemistry) |
| Zdroj: | Journal of Membrane Science. 60:219-232 |
| ISSN: | 0376-7388 |
| DOI: | 10.1016/s0376-7388(00)81536-7 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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