A charring agent semi-aromatic polyamides (PPTA) was synthesized via terephthaloyl chloride and 1,3-propanediamine through solution polycondesation at low temperature. The effects of reaction temperature, reaction time, and material ratios et al. on the inherent viscosity and yield of PPTA were investigated. The optimized synthesis conditions for PPTA were the polymeration temperature of 0 ℃, CaCl2 content of 4 g/100 mL solvent, reaction time of 4 h, monomer concentration of 0.7 mol/L, and material ratio （1,3-propanediamine∶terephthaloyl chloride）of 1.05∶1, respectively. The product was characterized by FTIR,1HNMR and TG tests. The effect of the intumescent flame retardant (IFR), comprised of PPTA for carbon sources and ammonium polyphosphate (APP) for acid sources, on ABS was studied. The results showed that the thermal degradation property of PPTA is similar to that of ABS and PPTA improved the flame retardancy and weight of residues at high temperature of ABS/APP system. SEM indicated that PPTA could promote the formation of compact intumescent charred layers in IFR-ABS system after burning.
