METHOD FOR PRODUCING POLYBENZIMIDAZOLES BASED ON 4,4'- DIPHENYLPHTHALIDE-DICARBOXYLIC ACID

摘要

The invention relates to a method for producing polybenzimidazoles based on 4,4'- diphenylphthalide-dicarboxylic acid and aromatic tetraamines by heating, consisting in carrying out reaction in the Eton reagent medium by increasing a temperature step-by-step from 80 to 150°C and adding phosphorus pentoxide in a quantity of 1-2 mol/mol monomers for binding condensation water. Said invention makes it possible to obtain a high-molecular, organic solvent-soluble, film-forming polybenzimidazole, the quantitative yield and molecular weight of which range from 40 000 to 100 000 and which is cross-linking reactive, by means of single-stage polycyclocondensation at high concentrations and a low temperature, thereby improving the ecological safety of the process and reducing the energy consumption thereof. Said type of polymers can be most efficiently used for producing high-heat and chemically resistant and high-strength materials (fibres,films and membranes).