Claims
- 1. A polyimide foam precursor which is a resinoid obtained by combining at least one alkyl ester of 3,3',4,4'-benzophenonetetracarboxylic acid; a meta- or para-substituted aromatic diamine which is free of aliphatic moieties; and a heterocyclic diamine, said ester(s) and said diamines being present in concentrations such that the imide forming functionalities are substantially equimolar, and the molar ratio of heterocylic diamine to tetracarboxylic acid diester being in the range of about 0.4-0.42 to 1.0.
- 2. A polyimide foam precursor as defined in either of the preceding claims 1 or 2 which also contains from about 0.00625 to about 0.05 weight percent of an effective surfactant.
- 3. A polyimide foam precursor as defined in either of the preceding claims 1 or 2 in which the heterocyclic diamine is 2,6-diaminopyridine and the aromatic diamine is p,p'-methylene dianiline.
Parent Case Info
This application is a division of application Ser. No. 252,902 filed Apr. 10, 1981, now U.S. Pat. No. 4,332,656.
Government Interests
The invention described herein was made in the performance of work under NASA Contract No. NAS9-15484 and is subject to the provisions of Section 305 of the National Aeronautics and Space Act of 1958 (72 Stat. 435; 42 USC 2457).
US Referenced Citations (5)
Divisions (1)
|
Number |
Date |
Country |
Parent |
252902 |
Apr 1981 |
|