Solvent resistant copolyimide
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorsAlice C. Chang, Terry L. St. Clair
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Abstract
A solvent resistant copolyimide was prepared by reacting 4,4'-oxydiphthalic anhydride with a diaimine blend comprising, based on the total amount of the diamine blend, about 75 to 90 mole percent of 3,4'-oxydianiline and about 10 to 25 mole percent p-phenylene diamine. The solvent resistant copolyimide had a higher glass transition temperature when cured at 350.degree. , 371.degree. and 400.degree. C. than LaRC.TM.-IA. The composite prepared from the copolyimide had similar mechanical properties to LaRC.TM.-IA. Films prepared from the copolyimide were resistant to immediate breakage when exposed to solvents such as dimethylacetamide and chloroform. The adhesive properties of the copolyimide were maintained even after testing at 23.degree., 150.degree., 177.degree. and 204.degree. C.
Claims16
A solvent resistant copolyimide comprising the following repeat units:
- ##STR3## wherein x is 75 to 90 mole percent of the copolyimide and y is 10 to 25 mole percent of the copolyimide.
A solvent resistant copolyimide prepared by reacting 4,4'-oxydiphthalic anhydride with a diamine blend comprising, based on the total amount of the diamine blend, about 75 to 90 mole percent of 3,4'-oxydianiline and about 10 to 25 mole percent of p-phenylene diamine and wherein the copolyimide has been endcapped with up to about 10 mole percent of a monofunctional aromatic anhydride and having unbalanced stoichiometry such that a molar deficit in the 4,4'-oxydiphthalic anhydride is compensated with twice the molar amount of the monofunctional aromatic anhydride.
Dependencies are inferred from the claim text.