Bayer Aktiengesellschaft

Klaus Elfert

Gerhard D Wolf

Hans J Rosenkranz

Francis Bentz

Rudolf Binsack

Jurgen Hinz

Hans E Kunzel

Hans Rudolf

Semipermeable composite membranes consisting of a microporous substrate and a semipermeable layer built of polymer material containing urazole structures.

Semipermeable membranes

The invention relates to membranes which consist of aromatic polyamides containing disulphimide groups and have relative viscosities .eta..sub.rel of .gtoreq.1.4 as measured on a 0.5% N-methylpyrrolidone solution at 20.degree. C., and which may be used for ultrafiltration and inverse osmosis. The membranes of these polyamides according to the invention have a high permeability to water, for example, a throughflow of 1000-5000 1/m.sup.2 d under a pressure of 20 bars, and a high retention capacity for dissolved substances.

Semipermeable membranes of aromatic disulfimide containing polyamides

A disulphimide group-containing acrylonitrile copolymer semi-permeable membrane which comprises:

Process of using a semi-permeable membrane of acrylonitrile copolymers

The invention relates to semipermeable membranes with a water absorption capacity of from 4.5 to 11% by weight, preferably from 4.5 to 8% by weight, as measured on approximately 40.mu. thick symmetrical films at room temperature and at 65% relative air humidity, a throughflow of 130 to 200 l/m.sup.2 d for a desalination level of 94.6 to 99.5% and consisting of an aromatic heterocycle-containing copolyamide with a relative viscosity of .gtoreq.1.4, as measured on a 0.5% N-methyl pyrrolidone solution at a temperature of 20.degree. C.

Semipermeable membranes of heterocyclic copolyamides

The invention relates to semipermeable membranes with a water absorption capacity of from 4.5 to 10% by weight preferably from 4.5 to 8% by weight as measured on approximately 40.mu. thick symmetrical films at room temperature and 65% relative air humidity, with a throughflow of at least 80 1/m.sup.2 d for a desalination level of at least 85% and consisting of a fully aromatic copolyamide with a relative viscosity of .gtoreq.1,4, as measured on a 0.5% N-methyl pyrrolidone solution at a temperature of 20.degree. C.

Semipermeable membranes of copolyamides

A process for separating an aromatic hydrocarbon of the general formula ##STR1## wherein R represents an alkyl group having 1 to 3 carbon atoms and

Separation of aromatic hydrocarbons from mixtures, using polyurethane

Semipermeable membranes of sulphonated polybenz-1,3-oxazin-2,4-diones for separating or enriching organic sulphonates by the method of inverse osmosis or ultrafiltration.

Semipermeable membranes of sulphonated polybenz-1,3-oxazin-2,4-diones

Novel, sulphonated polybenz-1,3-oxazin-2,4-diones are produced by reacting polybenzoxazin diones with chlorosulphonic acid in a molar ratio of from 1:1 to 1:10.

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Krefeld, Germany

Klaus Elfert