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Jan Ullsperger, Robert Valek
Properties of polymer solutions intended for formation of hollow fibers membranes by inversion phases process
Appl. Rheol. 28:6 (2018) 65935 (7 pages)
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The gas separation process by asymmetric polymeric membranes has received much attention during the last decades because
of its more energy efficiency than other conventional separation processes. Hollow fibers are the most favored membrane
geometry owing to their high surface area per unit volume of membrane module. One of the key elements determining the
potential and applications of asymmetric hollow-fiber membranes are the structural properties mainly including pore size,
pore distribution, selective layer thickness, molecular orientation and defectiveness. These elements can generally vary
depending on conditions during dry-jet wet-spinning process. Flow conditions in spinneret during extrusion are known to
affect the dense-layer of hollow fibers and possibly to enhance separation performance of hollow fibers. The aim of this study
was to determine flow conditions of polyetherimide/N-Methyl-2-pyrrolidone solvent/ethanol non-solvent spinning solutions
flowing through concentric annulus of spinneret during hollow fiber spinning process. The rotational rheometer was used to
characterize rheological properties of spinning solutions. Newtonian behavior of the spinning solutions with arbitrary composition
was shown. The effect of spinning solution and spinneret dimension on flow profile in spinneret was investigated.
The Newtonian character of the spinning solutions caused constant velocity profile resp. shear rate profile regardless of dope
composition when flowing through a spinneret with some flowrate. It has been shown the spinneret dimensions and geometry
play a crucial role in controlling the shear flow in spinneret. The phase behavior of the PEI/NMP/EtOH dope system at a temperature
of the hollow fiber spinning process (40oC) was studied.
► Cite this publication as follows:
Ullsperger J, Valek R: Properties of polymer solutions intended for formation of hollow fibers membranes by inversion phases process, Appl. Rheol. 28 (2018) 65935.
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