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Hollow fiber formation using Lewis acid : Base complex in the polymer solution
Author(s) -
Pereira C. C.,
Souza J. N. M.,
Nobrega R.,
Borges C. P.
Publication year - 2001
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.1510
Subject(s) - polymer chemistry , polymer , chemistry , lewis acids and bases , permeation , aqueous solution , chemical engineering , solvent , membrane , organic chemistry , catalysis , biochemistry , engineering
In the present work, hollow fiber formation was investigated by using Lewis acid : base complexes in the polymer solution. The studied systems consisted of poly(ether sulfone); N ‐methyl‐2‐pyrrolidone (NMP) as solvent and Lewis base, and acetic, propionic, n ‐caproic, and adipic acids as additives and Lewis acids. Bore liquid was formed by water/NMP solutions, as well as vaseline; whereas water was used as external precipitation bath. The spinneret and precipitation bath distance (i.e., air gap) also varied. The membranes were characterized by scanning electron microscopy and pure gas permeation tests. The influence of the complex dissociation rate was observed mainly when a reduction to water inflow from the bore liquid to the polymer solution occurred, because in this case, dissociation rate was inhibited. Therefore, stability was favored in the sublayer for a longer period, allowing macrovoid formation. These results are also evidenced by the permeability coefficients, which increased as fast as the polymer solution reaches water (i.e., the kinetics of precipitation was accelerated). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 908–917, 2001