Claims
- 1. A semipermeable membrane for separating substances prepared by
- exposing a shaped article of a water-soluble polymer or of a mixture of a water-soluble polymer and a water-insoluble polymer wherein the ratio of the water-soluble polymer to the water-insoluble polymer is 1 to 0.1-0.3 by weight to a plasma of a gas selected from the group consisting of helium, argon, nitrogen, hydrogen, oxygen, carbon monoxide, carbon dioxide, ammonia, a hydrocarbon having 1 to 10 carbon atoms, an epoxide having 2 to 10 carbon atoms, an alkylamine, or a mixture thereof to crosslink the surface layer of the shaped article, and then
- removing the uncrosslinked portions by washing with water.
- 2. The membrane of claim 1, wherein said water-soluble polymer is selected from the group consisting of polyethylene oxide, polyethylene glycol, polyvinylamine, polyacrylamide, polyacrylic acid, polyvinylpyrolidone, polyvinyl alcohol, and polyethyleneimine.
- 3. The membrane of claim 1, wherein said water-insoluble polymer is selected from the group consisting of polystyrene, polyethylene, natural rubber, polydimethylsiloxane, polyisobutene, polyvinyl acetate, and cellulose acetate.
- 4. The membrane of claim 1 having a thickness of no greater than 1.mu..
- 5. The membrane of claim 1 adapted for use in separating or concentrating substances by reverse osmosis or ultrafiltration.
- 6. The membrane of claim 1, wherein the crosslinked product is in the form of film, sheet, filament, or a composite with other porous support.
- 7. A membrane for separating substances, consisting essentially of a surface plasma-crosslinked product of a mixture of a water-soluble polymer and a water-insoluble polymer, the ratio of the water-soluble polymer to the water-insoluble polymer being from 1 to 0.1 to 0.3 by weight.
- 8. The membrane of claim 7, wherein said water-soluble polymer is selected from the group consisting of polyethylene oxide, polyethylene glycol, polyvinylamine, polyacrylamide, polyacrylic acid, polyvinylpyrolidone, polyvinyl alcohol, and polyethyleneimine.
- 9. The membrane of claim 7, wherein said water-insoluble polymer is selected from the group consisting of polystyrene, polyethylene, natural rubber, polydimethylsiloxane, polyisobutene, polyvinyl acetate, and cellulose acetate.
- 10. The membrane of claim 7 having a thickness no greater than 1.mu..
- 11. The membrane of claim 7, wherein the crosslinked product is in the form of a film, sheet, filament, or a composite with other porous support.
Priority Claims (2)
Number |
Date |
Country |
Kind |
48/101417 |
Sep 1973 |
JPX |
|
49/58578 |
May 1974 |
JPX |
|
Parent Case Info
This is a continuation of application Ser. No. 667,342, filed Mar. 16, 1976, now abandoned, which in turn is a division of application Ser. No. 503,701, filed Sept. 6, 1974, now U.S. Pat. No. 3,992,495.
US Referenced Citations (3)
Divisions (1)
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Number |
Date |
Country |
Parent |
503701 |
Sep 1974 |
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Continuations (1)
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Number |
Date |
Country |
Parent |
667342 |
Mar 1976 |
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