Low density, modified polyimide foams and methods of making same

US4621015A · kind A · utility

Inventors

• John V. Long · El Cajon, US
• John Gagliani · San Diego, US

Key dates

• Filing date: Mar 7, 1984
• Grant date: Nov 4, 1986
• Expiry date: Mar 7, 2004

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/31721
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Methods of making low density 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 oxime. 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. A suitable hydrated compound which is stable up to at least about 100.degree. C. is mixed with the powder. A foam is then 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. The addition of the hydrated compound is found to result in an exceptionally low density foam. Depending upon heating conditions, a polyimide, polyimide-amide or mixture thereof may be produced, resulting in foams having selectively variable physical properties.