Premium
A rationale for the preparation of asymmetric pervaporation membranes
Author(s) -
Mulder M. H. V.,
Hendrikman J. Oude,
Wijmans J. G.,
Smolders C. A.
Publication year - 1985
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1985.070300708
Subject(s) - pervaporation , membrane , chemical engineering , permeation , polymer , materials science , solvent , phase (matter) , homogeneous , selectivity , chromatography , polymer chemistry , chemistry , organic chemistry , composite material , catalysis , thermodynamics , biochemistry , physics , engineering
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.