Influence of compatibility in the EVA/starch/organoclay biodegradable nanocomposite on thermal properties and flame self-extinguishing behavior

Abstract

Thermal and flammability properties of ethylene vinyl acetate/starch/organoclay (EVA/S/C20A) nanocomposites are shown in this work. Wide-angle X-ray diffraction (WAXD) patterns and micrographs obtained by field emission scanning electron microscopy (FE-SEM) show the formation of nanostructured systems. The organoclay layers were preferably intercalated-exfoliated with the EVA polymer. Even so, the vinyl acetate group in EVA interacted with both the C20A clay and the starch macromolecules, achieving compatibility between the three components. The intercalated layers of clay provided protection against thermal degradation of the EVA. However, based on the kinetic study, the Ea of the nanocomposite degradation was lower than that of pure EVA. The flammability tests demonstrated the absence of dripping during burning and the self-extinguishing capacity of the flame (HB in the UL-94 test) in the EVA/C20A and EVA/S/C20A nanocomposites. The results are related to the nanointercalation of the clay and the compatibility between the three components with different properties. Thus, the flame self-extinguishing potential of ternary nanocomposites, previously studied as biodegradable, is demonstrated.