Ethyl Corporation

The United States of America As Represented by the Administrator of the

Mark W Beltz

Paul M Hergenrother

Venkataraman Ramachandran

Stephen J Havens

The semicrystalline polyimide prepared by reaction of 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) and 1,3-bis(4-aminophenoxy-4'-benzoyl)benzene (1,3-BABB) is modified so that it can be more readily processed to form adhesive bonds, moldings and composites. The stoichiometric ratio of the two monomers, BTDA and 1,3-BABB is controlled so that the intermediate polyamide acid is of a calculated molecular weight. A polyamide acid with excess anhydride groups is then reacted with the stoichiometrically required amount of monofunctional aromatic or aliphatic amine required for complete endcapping. A polyamide acid with excess amino groups is reacted with the stoichiometrically required amount of monofunctional aromatic anhydride required for complete endcapping. The stoichiometrically offset, endcapped polyimide is processed at lower temperatures and pressures than the unmodified high molecular weight polyimide with the same repeat unit, and exhibits an improved melt stability.

Polyimides with improved compression moldability

Substituted benzophenones are disclosed having the following formula ##STR1## where R.sub.A and R.sub.B are each independently COOH, C.sub.1 to C.sub.12 linear or branched alkyl or taken together to form an anhydride ring, R is nitro or amino unsubstituted or substituted with at least one C.sub.1 to C.sub.6 linear or branched alkyl, phenyl or substituted phenyl, the substituents being one or more C.sub.1 to C.sub.6 linear or branched alkyl or C.sub.6 to C.sub.10 aryl, Y and Y' are the same or different and are a chemical bond ##STR2## and m is 0 or 1 with the proviso that both R.sub.A and R.sub.B can not be hydrogen. Processes to produce these benzophenones are also disclosed.

Substituted benzophenone dicarboxylic acids

Benzophenone-type polyimides having repeating groups of the formula ##STR1## where Y and Y' are the same or different and are a chemical bond, --O--, --S--, ##STR2## --CH.sub.2 --, --C(CH.sub.3).sub.2 --, --CF.sub.2, --C(CF.sub.3).sub.2 -- or --Si(CH.sub.3).sub.2 -- and m is 0 or 1, are produced from monomers of the formula ##STR3##

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Baton Rouge, LA, United States of America

Mark W Beltz