Abstract: A method of making light weight flame resistant structures from bonded polyimide macroballoons and products thereof. An aromatic tetracarboxylic acid dianhydride is reacted with an oxoimine to produce an N-substituted imide, which is then esterfied with a suitable alcohol. The resulting liquid is dried and the dry residue is reduced to a uniform powder having particles with diameters generally in the 0.5 to 10 mm. range. The powder is preferably further dried, either before or after final size reduction, in a moderate vacuum at moderate temperature to remove any excess residual alcohol. The powder spontaneously expands to form a closed cell foam when heated to a temperature in the range of about 90.degree. to 150.degree. C. for a suitable period. When the powder is expanded in a closed mold, a well consolidated, uniform, closed cell foam product results. The closed cell foam produced has excellent flexibility and resistance to heat and flame, and does not shrink appreciably when exposed to flame.

Abstract: Methods of making modified polyimide/polyimide-amide foams having selected compressive resistance and density characteristics and the resulting compositions. An N-substituted aliphatic imide is prepared by reacting a suitable aromatic dianhydride with a suitable oxoimine. Within the mole ratio range of oxoimine to dianhydride of about 0.5:1 to about 0.05:1 the compressive resistance of the final foam can be selected in accordance with the intended end use of the foam. Density and compressive resistance varies inversely with the oxoimine quantity in the ratio, being greatest with the 0.5:1 ratio and lowest with the 0.05:1 ratio. A polyimide forming material is prepared by dissolving the N-substituted aliphatic imide in an esterifying solvent, then adding a suitable aromatic diamine. This material is dried to a powder or film. A foam is produced by heating the mateial to reaction temperature for a period sufficient to produce a stable foam.

Abstract: A high temperature and flame resistant closed cell polyimide foam material and methods of making the foam. An aromatic tetracarboxylic acid dianhydride is reacted with an oxomine to produce an N-substituted imide, which is then esterified with a suitable alcohol. The resulting liquid is dried and the dry residue is reduced to a uniform powder having particles with diameters generally in the 0.5 to 10 mm. range. The powder is preferably further dried, either before or after final size reduction, in a moderate vacuum at moderate temperature to remove any excess residual alcohol. The powder spontaneously expands to form a closed cell foam when heated to a temperature in the range of about 90.degree. to 150.degree. C. for a suitable period. When the powder is expanded in a closed mold, a well consolidated, uniform, closed cell foam product results. When expanded in an unrestricted manner, closed cell "macroballoons" having average diameters between about 0.4 to 15 mm. result.

Abstract: A high temperature and flame resistant closed cell polyimide foam material and methods of making the foam. An aromatic tetracarboxylic acid dianhydride is reacted with an oxomine to produce an N-substituted imide, which is then esterfied with a suitable alcohol. The resulting liquid is dried and the dry residue is reduced to a uniform powder having particles with diameters generally in the 0.5 to 10 mm. range. The powder is preferably further dried, either before or after final size reduction, in a moderate vacuum at moderate temperature to remove any excess residual alcohol. The powder spontaneously expands to form a closed cell foam when heated to a temperature in the range of about 90.degree. to 150.degree. C. for a suitable period. When the powder is expanded in a closed mold, a well consolidated, uniform, closed cell foam product results. When expanded in an unrestricted manner, closed cell "macroballoons" having average diameters between about 0.4 and 15 mm. result.

Abstract: Methods of making modified polyimide/polyimide-amide foams and the resulting compositions. An N-substituted aliphatic imide is prepared by reacting a suitable aromatic dianhydride with a suitable oxoimine. A polyimide forming material is prepared by dissolving the N-substituted aliphatic imide in an esterifying solvent, then adding a suitable aromatic diamine. This material is dried to a powder or film. A foam is produced by heating the material to reaction temperature for a period sufficient to produce a stable foam. The material melts, then spontaneously expands into a foam which becomes self supporting and cures to a resilient flexible foam. Depending upon heating conditions, a polyimide, polyimide-amide or mixture thereof may be produced, resulting in foams having varying physical properties.

Abstract: Closed cell polyimide foams. Methods of making such foams from precursors derived from a benzophenonetetracarboxylic acid diester and a mixture of diamines in which the precursor is molded to shape and cured, hydrated, and heated until a porous, closed cell structure develops.

Abstract: Polyimides of the formula ##STR1## Methods of making and polymerizing precursors for such polymers. Coating and adhesive compositions including constituents which can be converted into polyimides with the foregoing structure. Methods of making and using the compositions. Adhesion promoters for such compositions which are reaction products of aromatic dianhydrides and cyclic oxoimines, and methods of producing and using the adhesion promoters.

Abstract: Copolyimide foams made from lower alkyl esters of tetracarboxylic acids and two or more diamines. Precursors for such copolyimides. Processes for making the precursors and for converting them to copolyimide foams.

Abstract: Closed cell polyimide foams. Methods of making such foams from precursors derived from a benzophenonetetracarboxylic acid diester and a mixture of diamines in which the precursor is molded to shape and cured, hydrated, and heated until a porous, closed cell structure develops.

Abstract: Lightweight, compliant, structural members comprising an assemblage of metallic strips disposed in side-by-side relationship with the edges of the strips at opposite sides of the assemblage. The edges of the strips on one side of the assemblage may be folded over to provide a smoother, more continuous working surface. Point-to-point node bonding of adjacent strips and straight and nested foils at opposite sides of the assemblage can be utilized to facilitate handling and processing and to furnish lateral support.

Abstract: Lightweight, porous, compliant structural members comprising an assemblage of metallic strips disposed in side-by-side relationship with the edges of the strips at opposite sides of the assemblage. There are interstices between the strips, and the edges of the strips are fixed relative to each other on at least one side of the assemblage to maintain the strips in the proper relationship.

Abstract: Copolyimide foams made from lower alkyl esters of tetracarboxylic acids and two or more diamines. Precursors for such copolyimides. Processes for making the precursors and for converting them to copolyimide foams.

Abstract: Copolyimide foams made from lower alkyl esters of tetracarboxylic acids and two or more diamines. Precursors for such copolyimides. Processes for making the precursors and for converting them to copolyimide foams.

Abstract: Lightweight, porous, compliant structural members comprising an assemblage of metallic strips disposed in side-by-side relationship with the edges of the strips at opposite sides of the assemblage. There are interstices between the strips, and the edges of the strips are fixed relative to each other on at least one side of the assemblage to maintain the strips in the proper relationship.