Synthesis of novel azo-containing polyureas derived from 4-[4′-(2-hydroxy-1-naphthylazo)phenyl]-1,2,4-triazolidine-3,5-dione

4‐[4′‐(2‐Hydroxy‐1‐naphthylazo)phenyl]‐1,2,4‐triazolidine‐3,5‐dione (HNAPTD) (1) has been reacted with excess amount of n‐propylisocyanate in DMF (N,N‐dimethylformamide) solution at room temperature. The reaction proceeded with high yield, and involved reaction of both NH of the urazole group. The resulting bis‐urea derivative 2 was characterized by IR, 1H‐NMR, elemental analysis, UV‐Vis spectra, and it was finally used as a model compound for the polymerization reaction. Solution polycondensation reactions of monomer 1 with Hexamethylene diisocyanate (HMDI) and isophorone diisocyanate (IPDI) were performed in DMF in the presence of pyridine as a catalyst and lead to the formation of novel aliphatic azo‐containing polyurea dyes, which are soluble in polar solvents. The polymerization reaction with tolylene‐2,4‐diisocyanate (TDI) gave novel aromatic polyurea dye, which is insoluble in most organic solvents. These novel polyureas have inherent viscosities in a range of 0.15–0.22 g dL−1 in DMF at 25°C. Some structural characterization and physical properties of these novel polymers are reported. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3177–3183, 2001