Patent ID: 6172127
Filing Date: 2001-01-09
Classification: C08G,C08J

Abstract:
A method of preparing a polyimide foam comprising the steps of:a) adding to an aromatic ester solution, a carboxylic acid, an anhydride thereof or a mixture thereof, a divalent amine or a mixture of divalent amines in an amount equivalent to said carboxylic acid, a catalyst, and a surfactant to form a polyimide precursor, wherein said aromatic ester solution is produced by reacting an aromatic carboxylic acid or an anhydride thereof with an excess of an aliphatic univalent alcohol;b) preheating and then heating said polyimide precursor by means of a microwave oven to form a partially imidized and foamed polyimide precursor;c) curing said partially imidized and foamed polyimide precursor at a high temperature to form said polyimide foam;wherein said catalyst is isoquinoline, quinoline, imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, pyrrole, pyrazole, indole, pyridazine or pyrimidine.