Hyperbranched aromatic polyamines with s‐triazine rings

Two aromatic hyperbranched polyamines with s‐triazine rings were synthesized from A2 (4,4′‐sulfonyl dianiline or 4,4′‐methylene dianiline) and B3 (2,4,6‐trichloro‐s‐triazine) types of monomers by a single‐step nucleophilic displacement polymerization technique in the presence of diisopropyl ethyl amine as the base. The hyperbranched polyamines were obtained in high yields (∼ 82–90%) with this technique. The polymers were characterized through solubility testing, measurements of the inherent viscosity, Fourier transform infrared, ultraviolet, 1H‐NMR, and 13C‐NMR spectroscopy, and X‐ray diffraction studies. The inherent viscosities of the polymers were in the range of 0.23–0.42 dL/g in 0.5% (w/v) N,N′‐dimethylacetamide at 27 ± 0.1°C. They were soluble only in highly polar solvents such as N,N′‐dimethylacetamide, dimethylformamide, dimethyl sulfoxide, and N‐methylpyrrolidone. The thermal behavior of the polymers was investigated with thermogravimetric analysis and differential scanning calorimetry studies. The flame‐retardant characteristics of the polymers were tested through the measurement of the limiting oxygen index. In the thermogravimetric analysis of these hyperbranched polyamines, no weight loss was observed below 250°C under a nitrogen atmosphere, whereas differential scanning calorimetry showed that the glass‐transition temperatures were about 240 and 230°C for the polymers with sulfonyl and methylene groups, respectively.