1387448 Crosslinking polyacrylamide UNION CARBIDE CORP 30 June 1972 [2 July 1971 8 May 1972] 30653/72 Heading C3P [Also in Division H1] A method of crosslinking polyacrylamide comprises forming an aqueous solution of the polymer and adding thereto, with mixing, a watersoluble chromium-containing compound, wherein the chromium has a valency other than 3, and a water-soluble compound which will react with the chromium-containing compound to yield trivalent chromium ions. Preferred chromium compounds are dichromates (chromium valency = 6) such as ammonium, sodium, potassium and alkaline earth metal dichromates; suitable co-reactants for these include sulphite, bisulphite and thiocyanate salts of ammonia, alkali metals or alkaline earth metals. The crosslinking reaction can be carried out in situ between the anode and cathode of a dry, electrochemical cell to form a separator for the cell.
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