The deduction of fine structural details of gas separation hollow fibre membranes using resistance modelling of gas permeation

• Published in: Polymer (Guilford) Vol. 37; no. 3; pp. 485 - 492
• Main Authors: Shilton, S.J., Bell, G., Ferguson, J.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.02.1996; Elsevier
• Subjects: Applied sciences; Exact sciences and technology; Exchange resins and membranes; Forms of application and semi-finished materials; gas separation; hollow fibre membranes; Polymer industry, paints, wood; spinning conditions; Technology of polymers; spinning conditions; gas separation; hollow fibre membranes; Sulfone polymer; Porous membrane; Pore structure; Experimental study; Property processing relationship; Modeling; Gaseous permeation; Structure processing relationship; Gas permeability; Pore size; Solvent spinning; Concentration effect; Hollow fiber; Asymmetric membrane; Selective permeability
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/0032-3861(96)82919-3

Gas transfer through asymmetric polysulfone hollow fibre membranes has been modelled, allowing fine details of fibre structure to be deduced from gas permeation characteristics. The structural information is used to interpret the relationship between spinning conditions and fibre properties. Dope concentration determines the general morphology of the fibre, such as the porosity (voidage fraction), thickness of the active layer and order of magnitude of surface porosity (fraction of surface area that is pores), and thus it sets the permeability and level of selectivity that are likely to be achieved on coating. The selectivity of the solid polymer (the maximum selectivity achievable by any membrane if coating is highly effective or if no surface pores are present) was found to increase with increasing dope extrusion rate. The elevated levels of shear in the spinneret may enhance the orientation of polymer molecules. Increasing the jet stretch ratio during spinning had a detrimental effect on solid polymer selectivity. Increased elongational strain possibly results in an unfavourable polymer structure.