Abstract: An asymmetrical, microporous, hollow fiber membrane is made from a polymeric dope mixture of polysulfone and polyvinyl pyrrolidone dissolved in an aprotic solvent. The physical morphology of the hollow fiber membrane, i.e., the asymmetric microporous wall, is rapidly formed by passing the polymeric dope mixture through an outer annular orifice of a tube-in-orifice spinneret while simultaneously passing a precipitating solution through the central tube of the spinneret. The emerging hollow fiber travels substantially downward for about 0.01-10 m before submersion into a quenching bath. The asymmetrical, microporous, hollow fiber membrane is biocompatible and suitable for use in, for example, dialysis, hemodialysis, ultrafiltration, and water filtration applications.

Abstract: An asymmetric, microporous hollow fiber membrane comprising a polyimide is disclosed. The hollow fiber membrane is chemically inert to aqueous solutions and/or blood, is immediately rewettable after repeated steam and chemical sterilizations, has superior clearance, sieving, and water permeability characteristics and is usable over a wide range of applications such as dialysis and water filtration. Also disclosed is the process for manufacturing the polyimide hollow fiber membrane.