Simultaneously improving mechanical strength, hydrophobic property and flame retardancy of ethylene vinyl acetate copolymer/intumescent flame retardant/FeOOH by introducing modified fumed silica

Abstract

Series of flame-retardant ethylene vinyl acetate (EVA) composites with excellent properties were prepared by adjusting the fraction of fumed silica (FS). The surface morphologies, mechanical property, hydrophobicity, thermal property and the related flame-retardant properties were measured and investigated in details. The scanning electron microscopy (SEM) and mechanical property results showed that the certain addition of FS could effectively improve the interface compatibility between EVA matrix and flame retardant (FR). Moreover, the tensile strength and elongation at break were increased to 20 MPa and 675.0 %, respectively. High hydrophobicity of the EVA composite could also be achieved proved by high contact angle (85°) and low water absorption (0.2 %), respectively. In addition, cone calorimeter test (CCT) results indicated the value of heat rate release of EVA composites decreased by 63.6 % with the addition of FS compared to pure EVA due to the formation of char layer by protecting char residue and insulating fire and heat transmission, which was confirmed by SEM and thermogravimetric analysis (TGA) analysis. Besides, the anti-dripping effect of FS was indicated by limiting oxygen index (LOI) and UL-94.