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Modification of membrane permselectivity by graft copolymerization
Author(s) -
Ostler M. I.,
Rogers C. E.
Publication year - 1974
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.1974.070180507
Subject(s) - membrane , electrolyte , copolymer , chemical engineering , polymer chemistry , permeation , materials science , grafting , polymer , polymerization , potassium hydroxide , chemistry , electrode , composite material , biochemistry , engineering
The permselectivity and other performance characteristics of a polyethylene‐graft‐poly(potassium acrylate) copolymer membrane were considerably enhanced by subsequent grafting of polystyrene to the membrane. Careful control of the conditions of the grafting procedure, using cobalt‐60 gamma radiation initiation, allowed the preparation of membranes with prescribed graft compositions. The permeation behavior of the components of a silver oxide salt and concentrated potassium hydroxide solution were found to be very dependent on the graft content and its distribution in the membrane. The use of optimum polymerization conditions produced membranes in which the transport of the silver salt was reduced more than was that of the electrolyte, i.e., the ratio of silver salt flux to electrolyte flux was decreased by at least an order of magnitude. In addition, the resistance of the membrane to the degradation action of the two penetrating species was significantly increased. A structure model has been proposed which accounts for the observed property changes. These effects suggest that similar modifications may be useful for other polymer‐penetrant systems and applications.