Flame retardation performances of novel aryl cyclic phosphorus flame retardants when applied to highly flammable polymers

Abstract

A series of novel aryl cyclic phosphorus flame retardants (FR) has been synthesized in order to investigate their flame retarding performances for acrylonitrile-butadiene-styrene copolymer (ABS). They were synthesized in an attempt to obtain UL-94 V-0 rating when added to ABS as a single component FR. The fire behaviors and thermal stabilities of these compounds were investigated by micro calorimeter, thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). V-0 ratings are achieved at 20–30 wt% loadings of FR. FTIR results reveal that a part of the combusted phosphorus compound generates phosphorus volatiles, which are radical capturing species and actively quench the flame. The rest of the phosphorus compounds which are not volatile contribute to the formation of the residual char, which acts as a barrier layer protecting the intact portion of the ABS/FR mixture from further combustion. The evidence of interaction between FR and ABS can be obtained by observing the difference in the thermal behaviors of experimental determined and the calculated TGA thermograms. The presence of FR enhances the thermal stability significantly as well as decreases the peak heat release rate (PHRR) and total heat release (THR). This suggests that there is a considerable amount of contribution from the condensed phase action of FR although the gas phase action is dominant. Open image in new window