Preparation of Asymmetric Polysulfone Membranes. Analysis of Formation Process

C. PAGLIERO; N. OCHOA; J. MARCHESE

BOLETíN DE LA SOCIEDAD CHILENA DE QUíMICA

Sociedad Chilena de Química

Lugar: Concepción; Año: 1996 vol. 41 p. 321 - 330

0366-1644

Integrally skinned asymmetric flat membranes of polysulfone were prepared by wet phase inversion process. Scanning electron micrographs revealed that these membranes consist of an ultrathin skin layer, a tightly packed modular transition layer and two characteristic substructures underneath it: one is an open cell, sponge like substructure (polymer solution concentration higher than 10% w/w), and the other is a finger-like substructure (polymer solution concentration 10% w/w). The ternary phase diagrams of the system polysulfone/N,N-dimethylformamide/water and a mechanism based in different composition courses of a membrane volume element were used to explain membrane structure formation. It allows a qualitative explanation of three different structure formations.