ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Pervaporation is carried out primarily with homogeneous membranes. An improvement in permeation rate can be achieved by using asymmetric or composite membranes. In order to maintain a high selectivity, very dense top layers are needed. The formation of asymmetric pervaporation membranes will be discussed in terms of the model proposed by our group: formation of the top layer by gelation; formation of the porous sublayer by liquid-liquid phase separation followed by gelation of the concentrated polymer phase. To obtain very dense top layers the following factors are important: the ratio of nonsolvent inflow and solvent outflow, polymer concentration, location of the liquid-liquid demixing gap, and location of the gel region. Asymmetric membranes have been prepared by varying these factors, and the obtained membranes have been tested on ethanol/water mixtures.
Additional Material:
14 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1985.070300708
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