Claims
- 1. A process for producing activated carbon fibers of high adsorption capacity which contain about 80 to about 90 weight percent carbon, about 3 to about 15 weight percent nitrogen, about 2 to about 10 weight percent oxygen and less than 1 weight percent hydrogen, which comprises oxidizing an acrylonitrile based polymer which is a homopolymer of acrylonitrile, a copolymer containing about 60% by weight or more acrylonitrile, or a mixture of polymers such that about 60% by weight or more of acrylonitrile is present in the mixture, in an oxidizing atmosphere at a temperature of about 200.degree. C. to about 300.degree. C. while applying a tension to the fiber until the amount of bonded oxygen reaches about 65% to about 95% of the saturated amount of bonded oxygen of the fiber, wherein the tension applied is such that the shrinkage of the fiber during oxidation reaches about 70% to about 90% of the degree of free shrinkage at the same temperature, and then activating the fiber, wherein activation is by heating the oxidized fiber in a gas selected from CO.sub.2, NH.sub.3, steam or a mixture thereof at a temperature of about 700.degree. C. to about 1,000.degree. C. for 1 minute to 3 hours while the fiber is allowed to shrink freely, to thereby provide a specific surface area to said carbon fiber of from 300 m.sup.2 /g to 2,000 m.sup.2 /g, a tensile strength of about 20 to about 80 Kg/mm.sup.2, a tensile elongation of about 0.5 to 3% and a tensile modulus of about 1,500 to about 5,000 Kg/mm.sup.2.
- 2. The process according to claim 1, wherein the copolymer comprises acrylonitrile and at least one monomer copolymerizable therewith selected from the group consisting of vinyl chloride, vinylidene chloride, vinyl bromide, acrylic acid, methacrylic acid, itaconic acid, the salts of these acids, the alkyl esters of these acids in which the alkyl moiety has 1 to 4 carbon atoms, acrylamide, N-methylolacrylamide, allyl sulfonic acid, methallyl sulfonic acid, vinyl sulfonic acid, the salts of these acids, vinyl acetate, 2-hydroxyethylacrylate, 2-hydroxyethylmethacrylate, 2-hydroxyethylacrylonitrile, 2-chloroethylacrylate, 2-hydroxy-3-chloropropylacrylate, vinylidene cyanide and .alpha.-chloroacrylonitrile.
- 3. The process according to claim 1, wherein the oxidizing is in an oxidizing atmosphere containing about 15 vol% or more of oxygen.
- 4. The process according to claim 1, wherein the oxidizing is in an atmosphere of hydrogen chloride, sulfur dioxide, NO or NH.sub.3, each containing about 5 vol% to about 20 vol% of oxygen.
- 5. The process according to claim 1, wherein the activating is by heating the fiber in said activation gas after an aqueous solution of zinc chloride, phosphoric acid, sulfuric acid, hydrochloride acid, or sodium hydroxide has been deposited thereon.
- 6. The process according to claim 1, wherein the activating is after fabricating the oxidized fiber into the form of a woven fabric, a nonwoven fabric, or a felt.
- 7. The process according to claim 1, wherein said tension is attained by passing said fibers over a plurality of independent speed-variable rollers in such a manner that the running speed of the fiber is changed to apply constant tension to the fiber as the oxidation proceeds.
- 8. The process according to claim 1, wherein said activation gas is CO.sub.2.
- 9. The process according to claim 1, wherein said activation gas is NH.sub.3.
- 10. The process according to claim 1, wherein said activation gas is steam.
- 11. The process according to claim 1, wherein during activation the fiber is allowed to shrink freely.
- 12. The process according to claim 11, wherein the shrinkage is about 10% to about 30% based on the fiber oxidized.
- 13. The process according to claim 11, wherein the specific surface area of the fiber is increased during said activation.
- 14. The process according to claim 1, wherein said activating follows said oxidizing without an intermediate carbonization treatment.
- 15. An activated carbon fiber containing about 80 to about 90 wt% carbon, about 3 to about 15 wt% nitrogen, about 2 to about 10 wt% oxygen and less than about 1 wt% hydrogen, said activated carbon fiber having a specific surface area of about 300 to about 2,000 m.sup.2 /g, a tensile strength of about 20 to about 80 Kg/mm.sup.2, a tensile elongation of about 0.5 to 3% and a tensile modulus of about 1,500 to about 5,000 Kg/mm.sup.2.
- 16. The activated carbon fiber according to claim 15, wherein said fiber has a diameter of 3 to 15 microns.
- 17. The activated carbon fiber according to claim 15, produced by a process comprising oxidizing an acrylonitrile based fiber, which is a homopolymer of acrylonitrile a copolymer containing about 60% by weight or more of acrylonitrile, or a mixture of polymers such that about 60% by weight or more of acrylonitrile is present in the mixture, in an oxidizing atmosphere at a temperature of about 200.degree. C. to about 300.degree. C. while applying a tension to the fiber until the amount of bonded oxygen reaches about 65% to about 95% of the saturated amount of bonded oxygen of the fiber, wherein the tension applied is such that the shrinkage of the fiber during oxidation reaches about 70% to about 90% of the degree of free shrinkage, at the same temperature, and then activating the fiber, wherein activation is by heating the oxidized fiber in gas selected from CO.sub.2, NH.sub.3, steam or mixture thereof at a temperature of about 700.degree. C. to about 1,000.degree. C. for 1 minute to 3 hours while the fiber is allowed to shrink freely, to thereby provide a specific surface area to said carbon fiber of from 300 m.sup.2 /g to 2,000 m.sup.2 /g.
- 18. The process according to claim 1, wherein the amount of bonded oxygen is about 70 to 90% of the saturated amount of bonded oxygen of the fiber.
- 19. The process according to claim 1, wherein the activation gas contains at least one inert gas in an amount of about 0 to 50 volume %.
Priority Claims (1)
Number |
Date |
Country |
Kind |
51/118989 |
Oct 1976 |
JPX |
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CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part application of copending application, Ser. No. 785,888, filed Apr. 8, 1977.
US Referenced Citations (22)
Foreign Referenced Citations (2)
Number |
Date |
Country |
38-12376 |
Jul 1960 |
JPX |
49-116332 |
Nov 1974 |
JPX |
Non-Patent Literature Citations (1)
Entry |
Lin et al., "The Preparation and Properties of Activated Carbon Fibers Derived from Phenolic Precursor" Applied Polymer Symposium No. 21, 143-152 (1973). |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
785888 |
Apr 1977 |
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