ZUSAMMENFASSUNG:Poly(p-phenylen-I ,3,4-oxadiazol) (POD) ist aufgrund seiner thermischen Stabilitat, pH-und Ltjsungsmittelbestandigkeit ein interessanter Werkstoff zur Herstellung von Membranen. Die Herstellung von POD-Membranen und deren Trenneigenschaften im ProzeB der Ultrafiltration werden untersucht.
SUMMARYFor solving specific problems of separation, high demands on membrane materials will be made in relation to thermal stability and resistance in a wide pH-range and against organic solvents. Membranes from poly(p-phenylene-I ,3,4-oxadiazole) are prepared by different methods and their separation properties in ultrafiltration are investigated.
The ability of poly(2,6‐dimethyl‐1,4‐phenylene oxide) membranes to separate water‐ethanol mixtures by pervaporation was examined. Asymmetric membranes were prepared from solutions containing chloroform as a solvent and 1‐butanol as a nonsolvent by the phase‐inversion process. Homogeneous, dense membranes were prepared from chloroform solutions by evaporation. Nonporous membranes (membranes precipitated from solutions with a low amount of the nonsolvent or prepared by evaporation) were preferentially permeable to water. Microporous membranes (precipitated from solutions with a high amount of the nonsolvent) were preferentially permeable to ethanol, provided the membrane is not wetted by the feed solution.
Im wanrigen, schwermetallionenfreien Medium unterliegen die Amidoxim-und Hydroxamsauregruppen der Hydrolyse, und es entstehen an der Membranoberflache Carboxylgruppen, durch die mehrwertige Anionen zuruckgehalten werden. Ihr Vermogen zur Wasserenthartung bleibt erhalten.
SUMMARYThe chemical modification of polyacrylonitrile ultrafiltration (PAN-UF) membra-
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