Effects of silicon additive as synergists of Mg(OH)₂ on the flammability of ethylene vinyl acetate copolymer

Abstract

ABSTRACT:The present work dealt with the effects of nine kinds of silicon additives on flame retardancy of ethylene-vinyl acetate copolymer (EVA)/magnesium hydroxide [Mg(OH) 2 ] composites, as well as mechanical properties. The limiting oxygen index (LOI) test, horizontal fire test, vertical fire test, and cone calorimeter test were employed to evaluate flame retardancy of the composites. It was found that different silicon additives had different synergistic effects with Mg(OH) 2 on flame retardancy of the EVA matrix and exerted different influences on mechanical properties of the composites. The incorporation of organic montmorillonite (MMT) clay or silicone rubber not only made the composite reach FH-1 rating in the horizontal fire test and FV-1 rating in the vertical fire test, respectively, but also dramatically reduced the peak rate of heat release (Peak RHR) and increased the fire performance index (FPI) and ignition time (IT). The composites filled with precipitated SiO 2 exhibited the longest IT, the highest FPI, and FV-1 rating. However, only the composites filled with silicone rubber could attain a balance between mechanical properties and flame retardancy.

Synergistic flame retardant effects between sepiolite and magnesium hydroxide in ethylene-vinyl acetate (EVA) matrix

“…In recent years, many researches have published similar results related e.g. to zinc borate [3][4][5], multiwalled carbon nanotubes [6], Fe-MMT [7], layered double hydroxide [8], rubber [9], organo-modified montmorillonite [10], silicon [11], fumed silica [1], talc [12], expandable graphite [13], zinc hydroxystannate [14] and ammonium polyphosphate [15], combined with MH. Nevertheless, very few publications appear in the literature concerning the sepiolite used in combination with MH in EVA matrix.…”

A novel intumescent flame‐retardant system for flame‐retarded LLDPE/EVA composites

“…Therefore, it protects the underlying materials from the influence of heat and flame. To enhance the efficiency of IFRs, some synergistic agents have been used in IFR systems, such as zeolites,14 organoboron siloxane,15 and some transitional metal oxides16, 17 and montmorillonite (MMT),4, 18, 19 whose contribution involves the formation of a carbonaceous silicate char with a high performance 20–22. MMT, as a kind of clay with high surface area, is commonly used in polymer composite.…”

Fire-retardant and fire-barrier poly(vinyl acetate) composites for sealant application

“…In addition to the endothermic decomposition, the fire retardant slows the rate of thermal degradation of the polymer by dilution of the fuel supply with water vapour present in the gaseous phase. These factors, and its high heat capacity, reduce the thermal energy available to degrade the polymer [21].…”