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US 4,021,382 AGranted
Method for the preparation of hydrophilic spongy gels
AssigneeCeskoslovenska akademie ved
InventorsArtur Stoy, Vladimir Stoy, Miroslav Stol
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AssigneeCeskoslovenska akademie ved
InventorsArtur Stoy, Vladimir Stoy, Miroslav Stol
Estimating the term…
A method for the preparation of a hydrophilic acrylonitrile-containing polymer comprising admixing a solution of said polymer in 47% to 75%, preferably 50 to 72% concentrated HNO.sub.3, with solid particles of a substance insoluble in said acid solution and soluble in water, aqueous solutions of said substance being operative to precipitate said polymer from said HNO.sub.3, shaping the mixture of the dissolved polymer with said solid substance to a desired physical shape, coagulating said shaped polymer in an aqueous medium and washing said solid particles out from the coagulated polymer, and articles made therefrom. The added solid substance either may react with nitric acid forming a water-soluble nitrate, or it may remain in the mixture unchanged.
A method for the preparation of a spongy hydrophilic acrylonitrile-containing polymer comprising the steps of forming a solution of a polymer containing acrylonitrile in nitric acid having between 47 to 75% concentration with said polymer solution, admixing with said solution 10 to 90% by weight of a thickening agent comprising solid particles of a substance which is (a) insoluble in said acid solution, (b) soluble in water, and (c) being operative in aqueous solutions or its nitrate respectively to precipitate said polymer from said nitric acid, shaping the mixture of said polymer solution and solid particles to a desired physical shape, subsequently coagulating said shaped polymer in an aqueous medium, and thereafter washing said solid particles out of the coagulated polymer.
Dependencies are inferred from the claim text.