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Patent US3865841A successfully refreshed from Google Patents.
US3865841A
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US
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Benzothiophenedioxideisoquinoline polymers
Assignee: United States Department of the Air Force
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Filing: 1973-06-18
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Granted: 1975-02-11
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Expires: 1993-06-18
Abstract
Abstract Benzothiophenedioxideisoquinoline ladder polymers are synthesized by the condensation of 2,3,7,8tetraaminodibenzothiophene-5,5-dioxide with an aromatic tetracarboxylic acid or dianhydride thereof. The highly fused, aromatic-heterocyclic polymers so prepared have a high degree of thermal stability, a property that renders them particularly useful for high temperature applications, such as for plastic composites, fibrous materials and protective coatings.
Inventors
- 👤 Albert J Sicree
- 👤 Fred E Arnold
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:27
CPC Classifications
C; C07; C07D; C07D333/00; C07D333/50; C07D333/76; C08; C08G; C08G73/00; C08G73/06; C08G73/20
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
16 words
A THERMALLY STABLE FILM OR FIBER-FORMING POLYMER CONSISTING ESSENTIALLY OF RECURRING UNITS HAVING THE FOLLOWING FORMULA:
Claim 2
Dependent Claim
16 words
A THERMALLY STABLE FILM OR FIBER-FORMING POLYMER CONSISTING ESSENTIALLY OF RECURRING UNITS HAVING THE FOLLOWING FORMULA:
Claim 3
Dependent Claim
9 words
The polymer of claim 1 in which Ar is
Claim 4
Dependent Claim
9 words
The polymer of claim 1 in which Ar is
Claim 5
Dependent Claim
9 words
The polymer of claim 1 in which Ar is
Claim 6
Dependent Claim
9 words
The polymer of claim 1 in which Ar is
Claim 7
Dependent Claim
9 words
The polymer of claim 1 in which Ar is
References Cited (Backward Citations)
US3502625A
Cited
US3534003A
Cited
US3539537A
Cited
US3681284A
Cited
US3792024A
Cited
US3743624A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-10 | 1978-08-12 | 1979-02-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-10 | 1982-08-12 | 1983-02-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-10 | 1986-08-12 | 1987-02-11 | $7700.00 | Window Closed / Lapsed |