Influence of Layered Silicates on Shear Rheology of EVA Nanocomposites
Ranjit Prasad, Rahul Gupta, Sati N. Bhattacharya
RMIT University
Australia

Keywords: EVA, Nanocomposites, Intercalation

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Linear viscoelastic and steady shear rheology were conducted on ethylene-vinyl acetate copolymer (EVA)-layered silicate nanocomposites. Nanocomposites were prepared by melt mixing EVA and commercially acquired layered silicates (Cloisite 15A). Wide Angle X-Ray Scattering (WAXS) was used to ascertain the degree of layer swelling that could be attributed to the intercalation of polymer chains into the interlayer of the silicates. The nanocomposites prepared were predominantly intercalated in nature with certain degree of layered silicates retaining their original structure. In linear viscoelastic tests, both the 2.5wt% and 5wt% nanocomposites exhibited an increase in viscoelastic properties. The extent of property enhancement was not as pronounced as has been reported in many other instances with respect to other polymeric materials like Nylon 6. This could be attributed to the absence of a network structure that is essential for solid-like characteristic and weak interactions between the layered silicates and EVA chains. The steady shear viscosity results served only as a confirmation of the nature of the microstructure as ascertained by the linear viscoelastic tests.