ASYMMETRIC MEMBRANES AND PROCESS THEREFOR

摘要

There is disclosed an integral polymeric asymmetric ultrafiltration membrane and a process for preparing that membrane. The membrane comprises a skin and a support. The support comprises an open honeycomb structure. The polymer used to prepare the membrane may be any membrane forming polymer which has a glass transition temperature of at least about 200.degree.C. The process for preparing these ultrafiltration membranes comprises casting a solution comprising a solvent and less than about 13% by weight of the polymer into a quench liquid so that the polymer is substantially immediately precipitated as a solid membrane. The quench liquid should be a non-solvent for the polymer but be miscible with the solvent. The membranes produced by this process have a water permeability of at least about 0.2 cm/min psi.