The Rheological and Mechanical Properties of Ethylene-Vinyl Acetate (EVA) Copolymer and Organoclay Nanocomposites

Ethylene-vinyl acetate copolymer, EVA (containing 28% vinyl acetate (VA)) and organoclay, tallow benzyl dimethyl ammonium ion with montmorillonite (ranging from 1 to 8 wt%) were melt processed in order to determine the relationship between the polarity of the polymer matrix and the organoclay structure on the properties of the resulting nanocomposites. The effect of clay loading on the rheological and mechanical properties of the nanocomposites is systematically investigated. The intercalated nanocomposites showed a dependence of the properties on the amount of clay loading. Increasing the amount of clay resulted in an improvement in tensile strength and elongation at break. In addition the EVA/clay nanocomposites displayed an enhancement of both storage modulus, E′, and loss modulus, E′′, at low frequencies. Addition of clay decreased the flow activation energy, thereby enhancing the polymer melt flow. Thus clay acted as a lubricant for the EVA polymer.