Direct measurement of rheologically induced molecular orientation in gas separation hollow fibre membranes and effects on selectivity

A.F. Ismail, S.J. Shilton, I.R. Dunkin, S.L. Gallivan

Research output: Contribution to journalArticle

62 Citations (Scopus)

Abstract

Asymmetric polysulfone hollow fibre membranes for gas separation were spun using a dry/wet spinning process. An optimised four component dope solution was used: 22% (w/w) polysulfone, 31.8% (w/w) N,N-dimethylacetamide, 31.8% (w/ w) tetrahydrofuran and 14.4% (w/w) ethanol. Fibres were spun at low- and high-dope extrusion rates and hence at different levels of shear. Molecular orientation in the active layer of the membranes was measured by plane-polarised infrared spectroscopy. Gas permeation properties (permeability and selectivity) were evaluated using pure carbon dioxide and methane. The spectroscopy indicated that increased molecular orientation occurs in the high-shear membranes. The selectivities of these membranes were heightened and even surpassed the recognised intrinsic selectivity of the membrane polymer. The results suggest that increased shear during spinning increases molecular orientation and, in turn, enhances selectivity.
Original languageEnglish
Pages (from-to)133-137
Number of pages5
JournalJournal of Membrane Science
Volume126
Issue number1
DOIs
Publication statusPublished - 2 Apr 1997

Keywords

  • hollow fibre membranes
  • gas separation
  • spectroscopy
  • molecular orientation
  • enhanced selectivity

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