Abstract
The synthesis of hyperbranched polyamide (HPI) series containing s-triazine rings derived from melamine in the main chain took place according to an A3 + B2 approach, which entailed a conventional two-step method involving the emulsion polymerisation reactions of melamine in hydrochloric acid and stepwise thermal imidisation. The resulting HPIs were characterised by FT-IR and H-1-NMR spectroscopy, gel permeation chromatography, solubility tests, thermogravimetric analysis and differential scanning calorimetry. The influences of monomer feed ratio, reaction medium concentrations and reaction temperature were studied to find the optimal synthesis conditions. The HPI had imidised more than 88 % at 180 A degrees C, narrow molecular weight distribution in the range of 1.21-1.28, soluble in polar aprotic solvent, and thermally stable up to 450 A degrees C (except MB11HT and MB11HV) with glass transition temperature (T (g)) around 192 A degrees C. The excess feeding, either A3 or B2, determined the terminal group, while extending the reaction temperature decreased the yield of the product.