A novel approach has been proposed to enhance the flame retardancy of ABS by a highly efficient intumescent flame retardant coating, which was prepared by aluminum- ethylene glycol methyl propionate cyclohexanediol phosphonate (EMPCP-Al), polyvinyl formal (PVFO) and melamine cyanurate with specific ratio. When the average thickness of coating achieved at 106 mu m, the limit oxygen index value of ABS increased from 16.6 to 28.7, its UL-94 rating reached V-0 level in the vertical burning test, and the peak value of heat release rate (PHRR) was decreased by 51.1 compared with that of pure ABS. TGA coupled with Fourier transform infrared spectroscopy was used to probe the degradation behavior of the flame retardant composites. In addition, the microscopic morphology and graphitization degree of the carbon layer which obtained after the thermal degradation of the flame retardant composites were investigated by scanning electron microscopy-energy dispersive X ray and Raman spectroscopy. Moreover, P element, N element and Al element in flame retardant coating exhibited benign synergistic flame retardancy in the gas phase and condensed phase. Furthermore, the flame retardant coating could effectively avoid the damage to intrinsic mechanical properties of ABS caused by high loading of flame retardant additives.
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