Process of preparing polyamides and/or polyimides.

摘要

A polyamide and/or polyimide is prepared by using N,N'- dimethylethyleneurea or N,N'-dimethylpropyleneurea as a solvent for polycondensation of a polycarboxylic acid and a diisocyanate at a temperature above 100°C in the presence of an alkali metal carbonate, alkali metal hydrogencarbonate, alkali metal hydroxide or an alkali metal salt of a polycarboxylic acid. Where an alkali metal salt of a polycarboxylic acid is employed, the salt is preferably of an acid having the same or a similar structure to the polycarboxylic acid participating in the polycondensation reaction.