Akzo N.v.

Akzo Nobel N.v.

Heinz-Dieter Sluma

Jurgen Passlack

Alfons Leeb

Karl Bauer

Walter Loffelmann

Harald Schmitt

Heinz-Joachim Muller

Dieter Huff

Michael Schmitt

Ernst Spindler

Brigitte Buttner

Lothar Krauss

Marion Scherf

Karl Henke

Robert Weizenhofer

Gunter Eberhard

Helmut Volker

Robert Weinzenhofer

Polysulfone membrane and method for its manufacture

A multilayer membrane for separating gas mixtures includes a polymer supporting membrane with a voids volume of more than 50% and a coating of two or more separating layers made of two or more different polymers. A hollow capillary serving as the supporting membrane is guided through the central bore of a spinneret. The spinneret has one or several concentric annular slits and/or annular grooves, through each of which a solution of one of the polymers forming the separating layers is applied to the supporting membrane. The spinneret terminates in a sealed chamber in which the solvent or solvents of the polymer solutions is/are evaporated and removed. The coated supporting membrane is drawn out of the chamber and wound up, possibly following aftertreatment with heat and/or liquids.

Gas separation membrane

An asymmetric semipermeable membrane for dialysis and/or ultrafiltration is composed of a copolymer of acrylonitrile and acrylic ester and an ionic or ionizable monomer in the form of a hollow fiber. The copolymer is composed of 90.50 to 95.00 wt. % acrylonitrile, 4.99 to 8.60 wt. % acrylic ester, and 0.01 to 0.90 wt. % of the ionic or ionizable monomer. Also provided is a process for its manufacture.

Polyacrylonitrile membrane

A synthetic hydrophilic membrane, and method for manufacturing thereof, in the form of hollow fibers or flat membranes for dialysis and/or ultrafiltration, containing a mixture of polysulfone and sulfonated polysulfone, the mixture containing 65 to 95 wt.% sulfonated polysulfone, possibly as a salt of sulfonic acid, and 35 to 5 wt.% unsulfonated polysulfone. Preferably, up to 12 wt.% water-soluble polymers, based on the total mixture, are added to the mixture of polysulfone and sulfonated polysulfone before formation of the membrane.

Synthetic hydrophilic membranes and method for their manufacture

Method of making a multilayer capillary membrane

Membranes are based on a homogeneous mixture of polyvinylidene fluoride and a second polymer which can be rendered hydrophilic by chemical reaction. The membranes contain 70 to 98 percent by weight of polyvinylidene fluoride and 2 to 30 percent by weight of a polymer formed essentially from polymethyl and/or polyethyl acrylate, and have a maximum pore size in the range from 0.005 to 10 .mu.m. They can be rendered hydrophilic by means of at least partial hydrolysis, at least partial transesterification with an alcohol which is at least trihydric and contains 3 to 12 carbon atoms, and/or at least partial aminolysis with an amino compound having 2 to 8 carbon atoms. The flat or capillary membranes which have been rendered hydrophilic can contain on their total surface 0.001 to 10 milliequivalents/g of membrane, preferably 0.01 to 5 m equivalents/g of membrane, of --COOH, --OH or --NH.sub.2 groups or corresponding mixtures of these hydrophilic functional groups. Such membranes can be used, in particular, for immobilizing biochemically active compounds.

Flat or capillary membrane based on a homogeneous mixture of

The sulfonation of aromatic polyether sulfones in a controllable manner is possible by means of sulfur trioxide in concentrated sulfuric acid as solvent. By maintaining a sulfur trioxide content of less than 6 percent by weight, based on the solvent, and a reaction temperature of less than 30.degree. C., side reactions and degradation reactions are to a large extent suppressed. The resultant products are suitable for preparation of membranes.

Method for sulfonating aromatic polyether sulfones

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Grossostheim, Germany

Heinz-Dieter Sluma