Abstract: A method is provided for stabilizing polyamide acids of pyromellitic dianhydride and pyromellitic dianhydride copolymers utilizing certain silicon nitrogen compounds such as hexamethyldisilazane.

Abstract: Storage stable polyimide precursors are prepared from diesters of certain tetracarboxylic acids, including pyromellitic acid and 2,2-bis[4-(3,4-dicarboxyphenoxy)-phenyl]propane, and m-phenylenediamine, p-phenylenediamine, 4-aminophenyl ether or mixtures thereof. These polyimide precursors may be cured to form flexible polyimides useful in composite preparation.

Abstract: Zinc borate is added to high hydrocarbon content silicone containing compositions to reduce smoke emission.

Abstract: Polyetherimides are provided having chemically combined alkylaryl diamine units and method for making. The polyetherimides have similar T.sub.g 's over broad mol percent ranges to polyetherimides made from phenylene diamine units while providing economic cost advantages during manufacture.

Abstract: Polyetheramideimide is provided and method for making. There are utilized aromatic bis(etheranhydride) and diaminobenzanilide or mixtures thereof with an organicdiamine. The polyetheramideimide has been found to have improved solvent resistance.

Abstract: This invention is concerned with a method for plasticizing polyetherimide polymers with a reactive bisimide plasticizer. This invention also provides novel plasticized polyetherimide blends and rigid polyetherimide blends which are obtained by polymerizing the reactive bisimide plasticizer to form an interpenetrating matrix polymer. The plasticized blends exhibit melt viscosities and glass transition temperatures lower than those associated with the polyetherimide component of the blends. The rigid blends exhibit higher dimensional stability than polyetherimides. The blends produced are suitable for the manufacture of filaments, composites, fibers, films, molding compounds, coatings, etc.

Abstract: Bis-quaternary ammonium and phosphonium salts such as bis(tri-n-butyl)-1,6-hexylenediammonium dibromide are excellent phase transfer agents for the preparation of aromatic ether imides, as by the reaction of the disodium salt of bisphenol A with 4-nitro-N-methylphthalimide.

Abstract: A method for making aromatic ether imides is provided by effecting the displacement of reactive radicals on a phthalimide nucleus with a mono- or bis-alkali metal phenoxide in the presence of a nonpolar solvent and a phase transfer catalyst, such as a triorganoborate. The aromatic ether imide made by the present invention are useful intermediates for making aromatic ether anhydrides and aromatic bis(ether anhydrides).

Abstract: A method is provided for making aromatic bis(etherimide)s by effecting reaction between an aromatic bisphenoxide salt and a nitro-substituted N-alkyl phthalimide in the presence of a non-polar organic solvent and an effective amount of a phase transfer catalyst. There is utilized as the phase transfer catalyst, a mixture of a dipolar aprotic solvent and a polyvalent metal salt such as zinc chloride.