Effects of organoclay loading and ethylene glycol on mechanical, morphology and thermal properties of ethylene vinyl acetate/organoclay nanocomposites

Effects of organoclay loading (organophilic modified montmorillonite with octadecylamine) on the processing properties, tensile properties, morphology, thermal stability and water absorption behavior of ethylene vinyl acetate (EVA)/organoclay nanocomposites were studied. Organoclay loading from 2 to 10 phr was used as a filler in this study. The EVA/organoclay nanocomposites were produced using the melt compounding technique in an internal mixer, Haake Rheometer, at 120°C and 50 rpm of rotor speed. Ethylene glycol was used to compatibilize the polymer matrix-filler system. The ethylene glycol loading was maintained at 2 phr for all compounding systems. The results indicate that the processing torque increases gradually from 0 to 10 phr of organoclay loading. The tensile strength increases at 2 phr organoclay loading. Young's modulus increases with increasing organoclay loading which slightly reduces the elongation at break. The 2 phr of organoclay loading also showed better thermal stability and less water absorption. These enhanced properties are due to the homogenous dispersion of individual silicate layers in EVA matrix, which is evidenced from the structure that evaluated using X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). This exfoliation was achieved without the addition of compatibilizer. Interestingly, the presence of ethylene glycol reduces the processing torque, improves the tensile strength, elongation at break, and thermal stability of the EVA/organoclay nanocomposites.