Synergistic Flame Retardant Effect of SiO2in LLDPE/EVA/ATH Blends

Abstract

SiO2 has long been recognized as an inert diluent and usually used as an enhancing agent in thermoplastic polymers. Few reports are presented about its use as additive flame retardant. In this article, the flame retardant synergistic effect of SiO2 with aluminum hydroxide (ATH) on linear low density polyethylene and ethylene-vinyl acetate (LLDPE/EVA) composites in the presence of a new compatibilizer, polyethylene (PE) grafted by fluoropolysiloxane (FS), prepared to improve the compatibility between polymers (LLDPE/EVA) and inorganic fillers (ATH and SiO2), is investigated by means of limited oxygen index (LOI), cone calorimeter (CONE) and thermogravimetric analysis (TGA). The results show that the addition of SiO2apparently increases the LOI value and decreases the heat release rate (HRR), mass loss rate (MLR), and specific extinction area (SEA). The TGA data shows further evidence that the synergistic mechanism of SiO2 with ATH is mainly due to the physical process in the condensed phase leading to the formation of a more stable and compact barrier, which efficiently prevents the heat and mass transfer in fire. The good mechanical properties of the flame retardant materials implies the improved compatibility by the newly prepared compatibilizer.