METHOD FOR PRODUCING AROMATIC POLYIMIDES Russian patent published in 2023 - IPC C08G73/10 C07C45/00 C08L79/08 

FIELD: polymer chemistry.

SUBSTANCE: invention relates to methods for producing highly heat-resistant polyimides. A method for producing aromatic polyimides consists in carrying out a one-stage polycyclic condensation of one aromatic diamine with one tetracarboxylic acid or its dianhydride using a melt of aromatic monocarboxylic acids as a solvent, while the following pairs of monomers are used as monomers: 4,4'-bis (3-aminophenoxy)biphenyl - pyromellitic acid or its dianhydride, or 3,4-oxydianiline - oxydiphthalic acid or its dianhydride, or 3,4-oxydianiline - 3,3,4,4-biphenyl-tetracarboxylic acid or its dianhydride, or 1,3-bis-(4-aminophenoxy) benzene - 3,3,4,4-biphenyl-tetracarboxylic acid or its dianhydride, or 3,4-oxydianiline - 3,3',4,4'-benzophenone-tetracarboxylic acid or its dianhydride, or 1,3-bis-(4-aminophenoxy)benzene and oxydiphthalic acid or its dianhydride, which ensures the precipitation of the target product in the form of a thermoplastic partially crystalline powder.

EFFECT: approach proposed in the invention makes it possible to simplify the technology for producing polyimides, due to the spontaneous isolation of a solid reaction product, without the need to add an aliphatic monocarboxylic acid to the reaction mixture, which acts as a precipitant.

8 cl, 1 dwg, 1 tbl, 6 ex