Patent US5933649A successfully refreshed from Google Patents.
Patent US3705875A successfully refreshed from Google Patents.
US3705875A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermally stable polyimides
Assignee: United States Department of the Air Force
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Filing: 1971-08-11
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Granted: 1972-12-12
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Expires: 1991-08-11
Abstract
Abstract AROMATIC HETEROCYCLIC POLYIMIDES, THERMALLY STABLE AT HIGH TEMPERATURES, ARE PRODUCTED BY THE CONDENSATION OF 2,6-DIAMINOANTHRAQUINONE AND AN AROMATIC TETRACARBOXYLIC DIANHYDRIDE SUCH AS 1,4,5,8-NAPHTHALENETETRACARBOXYLIC DIANHYDRIDE. BECAUSE OF THE HIGH THERMAL STABILITY OF THE POLYIMIDES, THEY ARE EMINENTLY SUITABLE FOR USE IN VARIOUS AEROSPACE APPLICATIONS WHERE HIGH TEMPERTURES ARE ENCOUNTERED. IN PARTICULAR, THE POLYMERS ARE USEFUL FOR PRODUCING FILMS, FIBERS, LIMINATES, MOLDED ARTICLES AND ABLATIVE MATERIALS.
Inventors
- 👤 Charles E Browning
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:06
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) | 1975-12-12 | 1976-06-12 | 1976-12-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-12 | 1980-06-12 | 1980-12-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-12 | 1984-06-12 | 1984-12-12 | $7700.00 | Window Closed / Lapsed |