The potential use of natural expanded perlite as a flame retardant additive for acrylonitrile‐butadiene‐styrene based composites

Abstract

This study aimed to reveal the effect of expanded perlite (EP) additive as a flame retardant for acrylonitrile‐butadiene‐styrene (ABS) copolymer based composites. Before composite preparation, fine powdered EP was characterized by Fourier transform infrared spectroscopy, x‐ray diffraction, thermogravimetric analysis, and scanning electron microscopic analyses. Also, maleic anhydride grafted ABS (MAH‐g‐ABS) with a grafting degree of 3.9 wt% was synthesized and used as a polymeric compatibilizer. ABS/EP composites with different ratios of EP were prepared by a continuous one‐step melt mixing method. Thermogravimetric and morphological analysis, tensile tests, limiting oxygen index (LOI) and UL‐94 vertical burning tests of the composite materials were investigated. EP significantly decreased the decomposition rate of ABS and promoted char formation. EP provided a UL‐94 V‐1 flammability rating with great fire resistance and self‐extinguishing properties to the ABS matrix without any melt dripping. The LOI of ABS was greatly improved, reaching a value of 28.5% by adding only 5 phr EP. Zinc borate (ZB) also played a significant role in enhancing thermal stability and flame retardancy by creating a good synergism with EP. The composite containing 5 phr ZB showed a flame retardant grade of UL‐94 V‐0 and an LOI value of 27.5%.Highlights Flame retardant ABS/EP composites were successfully prepared by melt mixing. The EP ratio of 10 phr provided the highest resistance to flammability. ZB showed good synergy with EP in enhancing the flame retardancy of ABS. ABS/EP10/ZB‐5 composite had a UL‐94 V‐0 rating with an LOI value of 27.0%. This study proved the potential use of natural EP as a flame retardant filler.