Abstract：The effect of the intumescent flame retardant system on ABS/PA6(80/20)alloys was studied．The system was compounded with APP for acid sources and PA6 in ABS/PA6 alloys for carbon sources. The effect of different synergistic charring agents on the flame retardancy of the ABS／PA6 alloys was investigated, including pentaerythritol caged phosphate (PEPA), thermoplastic phenolic resin (TPPFR), epoxy resin (E-44) and Zeolite 4A. The results show that PA6 has the good effect of charring, When the wt% of APP is 25% , the limiting oxygen index (LOI) value was found to be 30 and the UL-94 measure be class V-1. When the wt% of APP is 35% , the UL-94 measure were found to be class V-0. The ABS/PA6/APP has the better flame retardancy when a little of synergistic charring agents (PEPA, E-44 or Zeolite 4A) were be added to the compound . The expansion, uniform, dense carbon layer formed on the surface of the complex after burning was observed by scanning electron microscopy (SEM).
