New polyamides containing azobenzene unites and hydantoin derivatives in main chain: synthesis and characterization

Eight new polyamides containing azo moieties and hydantoin groups were synthesized under microwave irradiation by using a domestic microwave oven from the polycondensation reactions of 4,4′-azodibenzoyl chloride [4,4′-azobenzenedicarboxylic acid] 3 with eight different derivatives of 5,5-disubstituted hydantoin 4a–h in the presence of a small amount of a polar organic medium such as o-cresol. The polycondensation proceeded rapidly, compared with the bulk polycondensation and the solution polycondensation and was completed between 7–12 min, producing a series of new polyamides 5a–h in high yield, and inherent viscosity between 0.35 and 0.60 dL/g. The resulting polyamides were characterized by elemental analysis, viscosity measurements, thermal gravimetric analysis (TGA and DTG), solubility test and FT-IR spectroscopy. All of the polymers were soluble at room temperature in polar solvents such as N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, tetrahydrofurane and N-methyl-2-pyrrolidone.