Patent US3801351A successfully refreshed from Google Patents.
US3801351A
Expired / Lapsed
US
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Treatment of high modulus graphite fibers to improve their bonding characteristics
Assignee: United States Department of the Air Force
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Filing: 1972-05-05
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Granted: 1974-04-02
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Expires: 1992-05-05
Abstract
Abstract A method of improving the bonding characteristics of high modulus graphite fibers is provided that comprises treating the fibers with a solution of osmium or ruthenium tetroxide and sodium iodate in water, dioxane or aqueous dioxane; washing and thereafter drying the treated fibers; contacting the treated fibers with a solution of tin tetrachloride in 2-butanone; and heating the fibers to remove the 2-butanone solvent. When graphite fibers so treated are used as a reinforcing material for epoxy resins, a composite is obtained that has a greatly improved interlaminar shear strength.
Inventors
- 👤 R Dauksys
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 10:05
CPC Classifications
D; D01; D01F; D01F11/00; D01F11/10; D01F11/14; C; C08; C08J; C08J5/00; C08J5/04; C08J5/06; C08K; C08K7/00; C08K7/02; C08K7/04; C08K7/06; D01F11/12
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
84 words
The method according to claim 1 in which the solvent for osmium or ruthenium tetroxide and sodium iodate contains in the range of 40 to 60 volume percent dioxane and 40 to 60 volume percent water; the solution contains from about 0.05 to 1.0 gram of osmium or ruthenium tetroxide and from about 25 to 200 grams of sodium iodate per liter of solvent; and the solution of tin tetrachloride contains from about 0.2 to 1.0 volume percent tin tetrachloride, based on the solvent.
Claim 2
Dependent Claim
17 words
The method according to claim 2 in which the solvent for the tin tetrachloride is a ketone.
Claim 3
Dependent Claim
12 words
The method according to claim 3 in which the ketone is 2-butanone.
Claim 4
Dependent Claim
75 words
The method according to claim 2 in which the solution of osmium or ruthenium tetroxide and sodium iodate is maintained at a temperature ranging from about room temperature to 90* C; the graphite fibers are immersed in the solution for a period ranging from about 1 minute to 8 hours; and the dried fibers are contacted with the tin tetrachloride solution at room temperature for a period ranging from about 15 seconds to 30 minutes.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-04-01 | 1977-10-01 | 1978-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-01 | 1981-10-01 | 1982-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-01 | 1985-10-01 | 1986-04-02 | $7700.00 | Window Closed / Lapsed |