US3702318A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermally stable heterocyclic anthraquinone polyimides and method for their synthesis
Assignee: United States Department of the Air Force
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Filing: 1971-08-11
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Granted: 1972-11-07
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Expires: 1991-08-11
Abstract
Abstract AROMATIC HETEROCYCLIC POLYIMIDES HAVING A HIGH THERMAL STABILITY ARE PROVIDED BY THE CONDENSATION OF 2,3,6,7ANTHRAQUINONETRACARBOXYLIC DIANHYDRIDE WITH AN AROMATIC DIAMINE, SUCH AS 2,6-DIAMINOANTHRAQUINONE. THE HIGH THERMAL STABILITY OF THE POLYMERS RENDERS THEM SUITABLE FOR USE IN MANY AEROSPACE APPLICATIONS WHERE HIGH TEMPERATURES ARE ENCOUNTERED. INPARTICULAR, THE POLYMERS ARE USEFUL FOR PRODUCING LAMINATES, MOLDED ARTICLES, FILMS, FIBERS, AND ABLATIVE MATERIALS.
Inventors
- 👤 Charles E Browning
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:30
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1067
Claims Analysis
Total Claims: 0
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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) | 1975-11-07 | 1976-05-08 | 1976-11-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-07 | 1980-05-08 | 1980-11-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-07 | 1984-05-08 | 1984-11-07 | $7700.00 | Window Closed / Lapsed |