1978 Volume 35 Issue 12 Pages 765-770
Poly (vinyl alcohol) -acrylonitrile graft copolymer membranes show good mechanical strength and solute permeability, but are poor in water permeability. The present work was undertaken to improve water permeability of the membranes without the decrease in the strength. The graft copolymer membranes were soaked in a mixed solvent of dimethyl sulfoxide and dimethylformamide at 60°C for 3 minutes and then immersed in water. Water content, mechanical properties, permeability of uric acid, vitamine B12 and water of the treated membranes were measured. Permeability was greatly improved by treatment with the solvent of suitable composition. The improvement is considered to be primarily owing to the increase in microporosity of the domains of polyacrylonitrile. The graft copolymer membranes had segregated microphase structure and the polyacrylonitrile phase was dispersed in the poly (vinyl alcohol) matrix.
