Synergistic effect of the charring agent on the thermal and flame retardant properties of polyethylene

A new charring agent (CA), a derivative of triazines, was synthesized. The flame retardancy and thermal behavior of a new intumescent flame-retardant (IFR) system for PE (PE-IFR) were investigated by limited oxygen index (LOI), UL-94 test, thermogravimetric analysis (TGA), and FTIR spectroscopy. The TG curves shows that the amount of residue of IFR-PE system are largely increased compared to those of PE at temperatures ranging from 350 to 700degreesC. The new PE-IFR system can apparently reduce the amount of decomposing products at higher temperatures and promotes the formation of carbonaceous charred layers. It showed a distinct synergistic flame retardant effect (SE) between nitrogen and phosphorus. The flame retardant PE composition was optimized to achieve a LOI value of 31.2 and UL-94 V-0 performance with the synthesized charring agent, ammonium polyphosphate (APP).