Melt Shear Rheology and pVT Behavior of Polypropylene / Multi-Walled Carbon Nanotube Composites

In this study, capillary rheological tests were performed on polypropylene filled with multi-walled carbon nanotubes (PP/MWCNT) to determine the melt flow curves and pressure-Volume-Temperature (pVT) diagrams. Based on the experimental data, master viscosity curves were constructed using the time-temperature-superposition principle and the Cross and Carreau-Winter models, while the pVT data were fitted to the Tait equation in both liquid and solid states. Results show that the melt shear viscosity decreases with increasing melt temperature and shear rate and increases with MWCNT wt.%. All composites display shear-thinning behavior in the range of medium to high shear rates. The specific volume of PP/MWCNT composite decreases with increasing MWCNT wt.% and pressure and increases with increasing temperature.