METHOD OF PREPARING POLYIMIDE MOULDING POWDER WITH HIGH IMIDISATION DEGREE

摘要

FIELD: chemistry.;SUBSTANCE: invention relates to production of polyimides and specifically to a method of producing polyimides in form of moulding powder. Single-step polycyclocondensation of one aromatic diamine with one tetracarboxylic acid or its dianhydride in an organic solvent is carried out. The organic solvent used is a mixture of one aromatic monocarboxylic acid and one aliphatic monocarboxylic acid. The aromatic monocarboxylic acid is an acid selected from: benzoic, o-methoxybenzoic, o-chlorobenzoic, m-nitrobenzoic, naphthalic, salicylic acid, and the aromatic diamine is specifically selected from: m-phenylenediamine, 4,4'-p-phenylenediamine, 4,4'-oxydianiline, 4,4'-methylenedianiline, and the tetracarboxylic acid or its dianhydride is tetracarboxylic acid or its dianhydride specifically selected from: pyromellitic acid, 3,3' ,4,4'-diphenyltetracarboxylic acid, 3,3',4,4'- benzophenone tetracarboxylic acid. If a mixture of acids is used as the solvent, the aromatic monocarboxylic acid is selected from: benzoic, o-methoxybenzoic, o-chlorobenzoic, m-nitrobenzoic, naphthalic acid and the aliphatic monocarboxylic acid is selected from: acetic, propionic and butanoic acid. The obtained moulding powder has particle size of 1-20 mcm, imidisation degree of not less than 90% and is meant for making articles through high-temperature pressure moulding at 370-500°C and for making articles through high-temperature pressure moulding at 280-500°C, extrusion and die casting.;EFFECT: simple technology, shorter synthesis time, exclusion of hard-to-remove high-boiling solvents from the process cycle and wider range of moulding powder obtained with retention of high degree of imidisation.;6 cl, 14 ex, 2 tbl