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Wet-phase-separation membranes from the polysulfone/N,N-dimethylacetamide/water ternary system: the formation and elements of their structure and propertiesČrtomir Stropnik,
Vladimir Kaiser,
Vojko Musil,
Milan Brumen, 2005, original scientific article
Abstract: Asymmetric and porous polysulfone (PSf) membranes were prepared by wet phase separation. Binary (PSf)/N,N-dimethylacetamide (DMA) solutions with polymer concentrations of 12.5-30 wt % were cast in thicknesses of 80-700 m and immersed in a coagulation bath of pure water. The morphology of the formed membranesć cross sections consisted of a cellular structure and macrovoidsč the cellular structure density was highest when the cast solution contained about 21 wt % PSf, regardless of the cast thickness. The membranesć pure waterpermeability decreased as the cast thickness increased. The instantaneousonset of the turbidity, regardless of the PSf content and cast thickness, its steep growth, and relatively high end value were the main characteristics of the turbidity phenomena taking place during the formation of the protomembranes. Again, the membrane-forming system with a PSf/DMA solution with about 21 wt % polymer, regardless of the cast thickness, had thehighest turbidity end value. The shrinkage of the cast solutions into the corresponding protomembrane was also examined quantitatively. Inverse experiments showed that the direction of the gravitation field had no influence on the shrinkage of the membrane-forming ternary system or the membranesć morphology and its water permeability.
Keywords: polymeric membranes, polysulfone asymmetric porous membranes, wet-phase separation, membrane preparation, morphology
Published in DKUM: 01.06.2012; Views: 2067; Downloads: 89
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