The effects of spinning conditions on the structure formation and the dimension of the hollow‐fiber membranes and their relationship with the permeability in dry–wet spinning technology

Abstract

Abstract Hollow‐fiber membranes were prepared by dry–wet spinning under different spinning conditions. The used spinneret was tube‐in‐orfice type and the membrane material was polysulfone (Udel P‐3500). N ‐methyl‐2‐pyrrolidinone (NMP) and water were used as solvent and coagulant, respectively. The concentration of the dope solution was 22 wt %. The effects of the three spinning factors—spinning height; extrusion rates of dope solution and inner coagulant; dimensions (inner diameter, outer diameter, and thickness) and permeation properties of the hollow‐fiber membranes—were studied. The results were as follows: With changes in the spinning factors, spinning velocity and falling time before the membrane entered the water (coagulant) were changed; consequently, the structures and the dimensions of the hollow‐fiber membranes varied with a certain tendency. The permeation properties of the hollow fibers were related very closely to the changes in the fibers' structures and dimensions. © 1995 John Wiley & Sons, Inc.