Ethylene vinyl acetate copolymer nanocomposites based on (un)modified sepiolite: Flame retardancy, thermal, and mechanical properties

Abstract

Flame retardant ethylene-vinyl acetate (EVA) nanocomposites were prepared by melt blending using unmodified and modified sepiolite. Modification process of sepiolite was carried out by using 3-aminopropyltrimethoxysilane in water/ethanol medium. Thermal, mechanical, and flame retardancy properties of the prepared nanocomposites were evaluated and compared with each other. X-ray diffraction and scanning electron microscopy indicated that sepiolite fibers are well-dispersed in EVA matrix. By the addition of (un)modified sepiolite, both flame retardancy and thermal stability characteristics first improved, and then deteriorated, indicating a direct relationship between these properties. It was also found that sepiolite protects carbonyl groups of EVA from further degradation. Most interestingly, a simultaneous increase in both ductility and toughness was observed in the prepared composites. Whatever the evaluated properties were, whether the mechanical, thermal, or flame retardancy, the improved properties were more remarkable when modified sepiolite was utilized.