Melt rheological properties of ethylene-vinyl acetate/multi-walled carbon nanotube composites

In this study, the rheological properties of Ethylene-Vinyl Acetate (EVA) filled with various contents (0.1 - 5 wt.%) of multi-walled carbon nanotubes (MWCNTs) were investigated using a capillary rheometer at temperatures and shear rates relevant to the injection molding process. The shear viscosity was calculated after the Bagley and Weissenberg-Rabinowitsch corrections, and the master curves were constructed applying the Time-Temperature Superposition (ITS) principle and the Cross model. The results show that, under shear flow, the EVA/MWCNT composites exhibit some of the key rheological behaviors. At low shear rates (lower than 100 s(-1)), the EVA/MWCNT composite behaves as Newtonian fluid for loading up to 0.5 wt.%, while at higher loading, the non-Newtonian behavior is more prominent. At shear rates higher than 100 s(-1), all composites exhibit shear thinning behavior (n < 0.4), indicating that the EVA/MWCNT composites are viable for the injection molding process. The dependence of shear viscosity on temperature is consistent with the Arrhenius equation and, for the investigated temperatures and shear rates, the viscosity increases linearly with increasing MWCNTs wt%. (C) 2016 Elsevier Ltd. All rights reserved.