ANIONIC HIGH-POLYMER SEPARATING MEMBRANE

摘要

PURPOSE:To obtain an anionic high-polymer separating membrane for a permeation evaporation method or vapor permeation method having satisfactory durability and a high permeation coefft. and sepn. coefft. by using the crosslinked matter of a vinyl polymer having a carboxyl group at the side chain. CONSTITUTION:A soln. mixture composed of an aq. soln. of polyacrylic acid and aq. soln. of melamine crosslinking agent such as hexamethoxymethyl melamine is cast on a porous supporting membrane such as ultrafilter membrane made of polyether sulfone and is immerdiately subjected to a heating treatment to progress a crosslinking reaction. Such film is further subjected to casting and heating in a similar manner to form the composite membrane having a skin layer of a desired thickness. The composite membrane is immersed into an aq. soln. of potassium acetate, etc., to convert the greater part of the carboxyl group in the membrane to potassium salt. The crosslinked membrane consisting of the metal salt of the polyacrylic acid is thus obtd.