Abstract: A novel polyamides charring agent (PPTA) was synthesized from terephthaloyl chloride and 1, 3-propanediamine through interfacial polymerization. The products were characterized using Fourier transform infrared spectroscopy (FTIR), 1H-NMR and thermogravimetric (TG) analysis. The effect of organic solvents, material ratio, and reaction time on the intrinsic viscosity of PPTA was investigated to confirm the optimized synthesis technique for PPTA. An intumescent flame retardant (IFR) comprised of PPTA as a carbon sources and ammonium polyphosphate (APP) as an acid sources was introduced into acrylonitrile-butadiene-styrene copolymer(ABS) and improved flame retardancy and increased char residue were observed. When the content of APP was 22.5 wt % and PPTA was 7.5 wt %, the limiting oxygen index of the composite was found to be 32.4 %, and grade V-0 of UL 94 test was passed. The microstructures of the composite indicated that PPTA promotes the formation of uniform and compact char layers in the composite after burning.

Key words: polyamides, charring agent, interfacial polymerization, intumescent flame retardant, acrylonitrile-butadiene-styrene copolymer