THE INFLUENCE OF PEG MOLECULAR WEIGHT ON MORPHOLOGIES AND PROPERTIES OF PVDF ASYMMETRIC MEMBRANES
| Autor: | Wei-lin Xu, You-yi Xu, Dan-ying Zuo, Han-tao Zou |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Materials science
Polymers and Plastics Precipitation (chemistry) General Chemical Engineering Organic Chemistry technology industry and agriculture Membrane structure macromolecular substances Casting Solvent chemistry.chemical_compound Membrane chemistry Chemical engineering Polymer chemistry PEG ratio Ethylene glycol Fluoride |
| Zdroj: | Chinese Journal of Polymer Science. 26:405 |
| ISSN: | 0256-7679 |
| DOI: | 10.1142/s0256767908003072 |
| Popis: | The preparation and properties of asymmetric poly(vinyldiene fluoride) (PVDF) membranes are described in this study. Membranes were prepared from a casting solution of PVDF, N, N-dimethylacetamide (DMAc) solvent and water-soluble poly(ethylene glycol) (PEG) additives by immersing them in water as coagulant medium. Experiments showed that when PEG molecular weight increased, the changes in the resultant membranes' morphologies and properties showed a transition point at PEG6000. This indicated that PEG with a relatively low molecular weight was used as a pore-forming agent to enhance pure water flux and reduce solute rejection of membranes, but PEG was used as a pore-reducing agent with a further increment of PEG molecular weight to result in pure water flux decreasing and solute rejection increasing. Finally, combined with the precipitation rates of different membrane-forming systems, the membrane formation mechanism describing PEG mobility was discussed extensively basing on the length changes of PEG molecular chains and the affinity between PEG and casting solution. The results offered a better understanding of effects of PEG additives on membrane structure and properties. |
| Databáze: | OpenAIRE |
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