Synthesis and characterization of poly(amide imides) containing benzimidazole-rings

New poly(amide imides) were prepared from benzimidazole-ring containing diamine via one-pot synthetic method. The diamine monomer, 6,4′-diamino-2-phenylbenzimidazole, was prepared from 4-nitrobenzoyl chloride and 4-nitro-1,2-phenylenediamine with 3 steps. It was found that the degree of imidization of the poly(amide imides) containing benzimidazole-ring can be controlled by monomer composition and solution imidization conditions. All partially imidized poly(amide imides) were soluble in polar aprotic solvent, but became insoluble in any organic solvents after thermal curing. The thermal stability of the poly(amide imides) increased as the polymers contain more benzimidazole units. Received: 6 March 1997/Accepted 2 April 1997