US4064109A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Perfluoroalkylene ether bibenzoxazole polymers
Assignee: United States Department of the Air Force
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Filing: 1976-07-30
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Granted: 1977-12-20
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Expires: 1996-07-30
Abstract
Abstract Perfluoroalkylene ether bibenzoxazole polymers are prepared by the polycondensation of perfluoroalkylene ether bis(o-aminophenol) compounds and perfluoroalkylene ether-imidate and -thioimidate esters synthesized by the reaction of certain perfluoroalkylene ether dinitriles with trifluoroethanol or ethanethiol. In addition to possessing high thermooxidative stability and good low temperature viscoelastic properties, the elastomeric polymers have a superior hydrolytic stability. This combination of properties renders the polymers particularly useful as seals and sealants in severe environments.
Inventors
- 👤 Robert C. Evers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:10
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/22
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
67 words
A polymer composition consisting essentially of recurring units having the following formula: ##STR14## a is 1 when b and c are each zero; b is 0.7 and c is 0.3 when a is zero; and x is an integer having a value such that the polymer has an inherent viscosity from 0.10 to 1.0 when measured at 25° C as a 0.2 weight percent solution in hexafluoroisopropanol.
Claim 2
Dependent Claim
67 words
A polymer composition consisting essentially of recurring units having the following formula: ##STR14## a is 1 when b and c are each zero; b is 0.7 and c is 0.3 when a is zero; and x is an integer having a value such that the polymer has an inherent viscosity from 0.10 to 1.0 when measured at 25° C as a 0.2 weight percent solution in hexafluoroisopropanol.
Claim 3
Dependent Claim
28 words
The polymer composition according to claim 1 in which R f is ##STR15## where m+n equals 5; and a is 1, and b and c are each zero.
Claim 4
Dependent Claim
28 words
The polymer composition according to claim 1 in which R f is ##STR16## where m+n equals 5; and a is 1, and b and c are each zero.
Claim 5
Dependent Claim
28 words
The polymer composition according to claim 1 in which R f is ##STR17## where m+n equals 5; and a is 1, and b and c are each zero.
Claim 6
Dependent Claim
24 words
The polymer composition according to claim 1 in which R f is ##STR18## and a is zero, b is 0.7, and c is 0.3
Claim 7
Dependent Claim
24 words
The polymer composition according to claim 1 in which R f is ##STR19## and a is zero, b is 0.7, and c is 0.3.
References Cited (Backward Citations)
US3846374A
Cited
US3810874A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-12-19 | 1981-06-20 | 1981-12-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-12-19 | 1985-06-20 | 1985-12-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-12-19 | 1989-06-20 | 1989-12-20 | $7700.00 | Window Closed / Lapsed |