US4115367A
Expired / Lapsed
US
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Perfluoroalkylene ether bibenzoxazole polymers
Assignee: United States Department of the Air Force
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Filing: 1977-07-21
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Granted: 1978-09-19
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Expires: 1997-07-21
Abstract
Abstract Thermooxidatively and hydrolytically stable perfluoroalkylene ether bibenzoxazole polymers having improved viscoelastic properties are synthesized by the polycondensation of perfluoroalkylene ether bis(o-aminophenol) compounds with thioimidate esters derived primarily from tetrafluoroethylene oxide but end-capped with hexafluoropropylene oxide. Based on their lower glass transition temperature, the polymers have a very broad use temperature range which renders them particularly useful under severe environmental conditions encountered in aerospace elastomer applications such as seals and sealants.
Inventors
- 👤 Robert C. Evers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:05
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/22
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
86 words
A perfluoroalkylene ether bibenzoxazole polymer consisting essentially of recurring units having the following formula: ##STR17## wherein R f ' is (CF 2 ) 2 O(CF 2 ) 2 O(CF 2 ) 2 , (CF 2 ) 2 O(CF 2 ) 5 O(CF 2 ) 2 or (CF 2 ) 2 O(CF 2 ) 5 O(CF 2 ) 2 O(CF 2 ) 2 O(CF 2 ) 2 ; ##STR18## where (x+y) equals 5 or 6, or ##STR19## and n is an integer equal to at least 2.
Claim 2
Dependent Claim
86 words
A perfluoroalkylene ether bibenzoxazole polymer consisting essentially of recurring units having the following formula: ##STR17## wherein R f ' is (CF 2 ) 2 O(CF 2 ) 2 O(CF 2 ) 2 , (CF 2 ) 2 O(CF 2 ) 5 O(CF 2 ) 2 or (CF 2 ) 2 O(CF 2 ) 5 O(CF 2 ) 2 O(CF 2 ) 2 O(CF 2 ) 2 ; ##STR18## where (x+y) equals 5 or 6, or ##STR19## and n is an integer equal to at least 2.
Claim 3
Dependent Claim
29 words
The polymer according to claim 1 in which R f ' is (CF 2 ) 2 O(CF 2 ) 2 O(CF 2 ) 2 and R f is ##STR20##
Claim 4
Dependent Claim
33 words
The polymer according to claim 1 in which R f ' is (CF 2 ) 2 O(CF 2 ) 5 O(CF 2 ) 2 and R f is ##STR21## where (x+y) equals 5.
Claim 5
Dependent Claim
33 words
The polymer according to claim 1 in which R f ' is (CF 2 ) 2 O(CF 2 ) 5 O(CF 2 ) 2 and R f is ##STR22## where (x+y) equals 6.
Claim 6
Dependent Claim
29 words
The polymer according to claim 1 in which R f ' is (CF 2 ) 2 O(CF 2 ) 5 O(CF 2 ) 2 and R f is ##STR23##
Claim 7
Dependent Claim
39 words
The polymer according to claim 1 in which R f ' is (CF 2 ) 2 O(CF 2 ) 5 O(CF 2 ) 2 O(CF 2 ) 2 O(CF 2 and R.sub. f is ##STR24## where (x+y) equals 6.
Claim 8
Dependent Claim
37 words
The polymer according to claim 1 in which R f ' is (CF 2 ) 2 O(CF 2 ) 5 O(CF 2 ) 2 O(CF 2 ) 2 O(CF 2 ) 2 and R f is ##STR25##
References Cited (Backward Citations)
US3846376A
Cited
US3994861A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-09-18 | 1982-03-20 | 1982-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-09-18 | 1986-03-20 | 1986-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-09-18 | 1990-03-20 | 1990-09-19 | $7700.00 | Window Closed / Lapsed |