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Preparation of porous hollow fiber membranes with a triple‐orifice spinneret
Author(s) -
He T.,
Mulder M. H. V.,
Wessling M.
Publication year - 2003
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.11591
Subject(s) - membrane , materials science , porosity , cloud point , body orifice , chemical engineering , polymer , diffusion , microfiltration , fiber , polymer chemistry , composite material , chemistry , thermodynamics , pulmonary surfactant , ecology , biochemistry , engineering , biology , physics
A triple‐orifice spinneret has been applied for the preparation of hollow fiber microfiltration membranes with a high surface porosity. Considering the general rules of diffusion induced phase separation, a low polymer concentration is required at the outer layer to obtain a highly interconnected open‐porous structure. Therefore, by using N‐methylpyrrolidone (NMP) as the external liquid at the outside orifice of the spinneret, a highly porous surface can be obtained. For a polymer solution containing a low molecular weight additive and with an initial concentration close to the cloud point, this technique shows slightly improvement on the pure water and gas fluxes since the major resistance of the membrane is located at the substructure and the inner skin. However, for a solution containing a high molecular weight additive and with an initial concentration far from the cloud point, a porous shell surface is obtained, resulting in a significant improvement in water flux. The effect of various external liquids on the morphology has been investigated as well. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2151–2157, 2003