US3931392A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Enhancement of ultimate tensile strength of carbon fibers
Assignee: United States Department of the Navy
•
Filing: 1974-01-10
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Granted: 1976-01-06
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Expires: 1994-01-10
Abstract
Abstract A method of enhancing the tensile strength of carbon fibers of laboratory and commercial materials. Carbon fibers are immersed at ambient temperatures in liquid bromine or bromine dissolved in a solvent within a chemical resistant container for a period of time, the bromine is then removed by flushing with an inert gas. The removed bromine may be recovered and reused by condensing the vapor; small traces of bromine may remain within the fiber. It has been found that the bromine treatment enhances the tensile strength of the treated fiber.
Inventors
- 👤 Victor R. Deitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:25
CPC Classifications
D; D01; D01F; D01F11/00; D01F11/10; D01F11/12; D01F11/121; Y; Y10; Y10S; Y10S264/00; Y10S264/19
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
89 words
A method of treating carbon fibers to enhance their tensile strength; which comprises, immersing said carbon fibers in liquid bromine within a container for a period of from about one hour to several day at ambient temperature; removing any excess bromine from said container and said fibers; subsequent to the disappearance of any coloration due to bromine vapor, heating the treated carbon fibers at a temperature of from about 150°C to about 250°C for about 1 hour, and cooling said heated fibers within a helium atmosphere to ambient temperature.
Claim 2
Independent Claim
89 words
A method of treating carbon fibers to enhance their tensile strength; which comprises, immersing said carbon fibers in liquid bromine within a container for a period of from about one hour to several day at ambient temperature; removing any excess bromine from said container and said fibers; subsequent to the disappearance of any coloration due to bromine vapor, heating the treated carbon fibers at a temperature of from about 150°C to about 250°C for about 1 hour, and cooling said heated fibers within a helium atmosphere to ambient temperature.
Claim 3
Dependent Claim
27 words
A method as claimed in claim 1; wherein said bromine is removed from said fibers by flushing the treated fibers with an inert gas at room temperature.
Claim 4
Dependent Claim
13 words
A method as claimed in claim 2; wherein said inert gas is helium.
Claim 5
Dependent Claim
26 words
A method as claimed in claim 3; wherein said treated carbon fibers are heated to a temperature of about 240°C subsequent to flushing with said helium.
Claim 6
Dependent Claim
12 words
A method as claimed in claim 4; wherein said temperature is 150°C.
Claim 7
Dependent Claim
12 words
A method as claimed in claim 4; wherein said temperature is 200°C.
Claim 8
Dependent Claim
52 words
A method as claimed in claim 3; wherein prior to removing said excess bromine said bromine immersed fibers within said container are immersed in an ice bath for a period of about 12 hours; and subsequent to cooling said fibers, warming said fibers to room temperature prior to removing said excess bromine.
Claim 9
Dependent Claim
22 words
A method as claimed in claim 3; wherein, said bromine removed from said carbon fibers is condensed and saved for further use.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-01-05 | 1979-07-07 | 1980-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-05 | 1983-07-07 | 1984-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-05 | 1987-07-07 | 1988-01-06 | $7700.00 | Window Closed / Lapsed |