Capillary Extrusion Rheology and Thermal Stability of EVA/Organomontmorillonite Nanocomposites

Ethylene vinyl acetate (EVA) co-polymer-based nanocomposites based on organomontmorillonite (Org-MMT) (Nanolin DK) were prepared by melt compounding without any additional compatibiliser. A partially-intercalated partially-exfoliated structure was revealed in the nanocomposites by X-ray diffraction and transmission electron microscopy Attention was paid to the steady shear rheological properties of the nanocomposites via a capillary rheometer owing to the resemblance of its conditions of operation to those prevailing during the practical fabrication process of materials. Increasing the temperature improves the flow properties but decreases the pseudoplasticity of the melts. With increasing shear stress (or shear rate), the shear viscosity (η) and flow activation energy ( E _η ) drop while the extrudate swell ratio ( d _e / d _c ) rises. The addition of Org-MMT leads to a reduction in both η and d _e / d _c of the nanocomposites as compared to the EVA matrix. The thermal stability of EVA and EVA/Org-MMT nanocomposites was also examined by thermogravimetric analysis