High efficiency intumescent flame retardancy between Hexakis (4-nitrophenoxy) cyclotriphosphazene and ammonium polyphosphate on ABS

Abstract

Hexakis(4-nitrophenoxy) cyclotriphosphazene (HNTP) with ammonium polyphosphate (APP) were added to acrylonitrile–butadiene–styrene copolymer (ABS) to improve the intumescent flammability and thermal properties of ABS. The effect of intumescent flame retardancy was characterized by limited oxygen index (LOI), vertical burning test (UL-94), thermos gravimetric analysis (TGA) tests, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). When the loading of ABS, HNTP and APP were 70, 15 and 15%, respectively, the LOI value reached 25.6 and UL-94 test was V-0. The TGA showed the high char yield of ABS/30%HNTP system at high temperatures. The experimental and theoretical TG curves and FTIR indicated that HNTP and APP promoted the form of cross-link structure, which acted as a barrier near the surface of material. The SEM further revealed the formation morphology of intumescent charred layer on ABS/15%HNTP/15%APP system. Tensile tests provided the possibility of using HNTP at high temperature.