Abstract:Polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS) blend is an important industrial plastic alloy due to its overwhelming advantages. However, the addition of ABS causes deterioration of flame retardancy for PC/ABS blend, therefore, it’s significant to improve flammability of PC/ABS blends. For the demand of environmental protection, aryl phosphate ester is an effective substitute for halogen flame retardant. In this research, aromatic phosphate ester (TPP) and alpha zirconium phosphate (α-ZrP) were used as flame retardant for PC/ABS blends, and their thermal properties and flame retardancy were studied. Thermogravimetic (TG) analysis in nitrogen atmosphere indicate that TPP and α-ZrP could markedly enhance the thermal stability, especially at high temperature. TPP and α-ZrP do not show great synergistic effect in vertical burning (UL 94) and limited oxygen index (LOI) tests. However, the cone calorimetry results indicate that TPP and α-ZrP not only enhance the flame retardancy of PC/ABS, but extend the burning time and slow down the process of combustion.