Patent ID: 9181384
Filing Date: 2015-11-10
Classification: B01D,C08G

Abstract:
1. A process for synthesizing an integral asymmetric polyurethane membrane comprising: a) polymerizing a first pre-polymer and a second pre-polymer, dissolved in a mixture of a first solvent, a second solvent and a catalyst, thereby providing a solution of a polyurethane; b) casting the solution, thereby providing a cast solution; c) evaporating the cast solution for a time period between about 30 to 100 seconds, thereby initiating formation of a first polymer layer having a cross-section with a thickness ranging from about 0.1 to 1 μm; d) extracting the first solvent by exchange with a non-solvent, thereby providing an integral asymmetric polyurethane membrane comprising the first polymer layer and a second polymer layer having a cross-section thickness of around 100 μm; e) immersing the integral asymmetric polyurethane membrane in water or an aqueous solution, thereby removing residual catalyst and solvents; and f) drying the integral asymmetric polyurethane membrane wherein the second solvent evaporates before the first solvent.