The mechanism study on the cooperative flame resistance effect between HMP and NP in ABS by TG–FTIR

Abstract

Thermogravimetry (TG) coupled with Fourier transform infrared spectroscopy (FTIR) (TG–FTIR) is an effective tool on studying the mechanism of the flame retardant. The mechanism on the cooperative effect between hydroquinone bis(di-2-methylphenyl phosphate) (HMP), which is an effective flame retardant, and novolac phenol (NP) in acrylonitrile–butadiene–styrene (ABS) is investigated by TG–FTIR under air in this study. The TG–FTIR of ABS/HMP, ABS/HMP/NP and ABS/NP are discussed carefully as well as their semi-quantitative analyses. The semi-quantitative analysis results of TG–FTIR show that ABS/HMP, ABS/HMP/NP and ABS/NP decompose in a two-step process. The first step is mainly the process of thermal degradation, macromolecules being decomposed into micromolecules containing many functional groups such as CAr–H, –CH2–, –OH, P–O–CAr. The second step is mainly the process of combustion, the layer of carbon being further oxidized into carbon dioxide, water and alkyne. The residue of ABS/HMP/NP is the highest as well as its temperature at which the maximum of mass loss rate occurs. Furthermore, the comparison of their semi-quantitative analyses indicates that NP could absorb parts of micromolecules containing the functional groups of –OH, CH2– and CAr–H, contributing to the formation of carbon layer, and HMP slows down the degradation of the carbon layer, achieving the cooperative effect.