Synthesis and Application of a Novel Charring Agent Poly(p-ethylene terephthalamide)

Abstract

A novel charring agent poly(p-ethylene terephthalamide) (PETA) was synthesized by using terephthaloyl chloride and ethylenediamine through solution polycondensation at low temperature. Poly(p-ethylene terephthalamide) was used together with ammonium polyphosphate (APP) to prepare a novel intumescent flame retardant (IFR) for acrylonitrile–butadiene–styrene (ABS). The thermal degradation behavior and flame retardancy were investigated by thermogravimetric analysis and limiting oxygen index (LOI) tests, and the morphology and structures of residues generated in different conditions were investigated by scanning electron microscopy and Fourier transform infrared spectra. The results showed that PETA could be effective as a charring agent, the flame retardancy of ABS and the weight of residues improved greatly with the addition of IFR. When the content of APP was 25 wt% and PETA was 12.5 wt%, the LOI value of IFR–ABS system was found to be 33, and class V-0 of UL-94 test was passed. The microstructures observed by scanning electron microscope indicated that the charring agent (PETA) can promote formation of uniform and compact intumescent charred layers in IFR–ABS system after burning.

Keywords:

• charring agent
• intumescent flame retardant
• poly(p-ethylene terephthalamide)

Acknowledgment

We would like to thank the generous financial support by National Natural Sciences Foundation of China, grant no. 50973066.