Rheology of a polypropylene/low-density polyethylene blending melt: Fitting dynamic rheological data by Palierne model and Lee and Park model

Abstract

The dynamic rheological behavior of polypropylene (PP)/low-density polyethylene (LDPE) blending melts at 210 °C and 230 °C was measured by small-amplitude oscillatory shear mode on a rotational rheometer. The complex viscosity and dynamic modulus of pure PP are higher than those of pure LDPE at low frequency. For the blends with dispersion morphologies, Palierne model is applied to fit the storage modulus data and the model almost underestimates the data since most of the experimental dynamic modulus of the blends lay between that of pure PP and pure LDPE. While Lee and Park model predicts the dynamic storage data well for the PP/LDPE blends 90/10, 10/90 and 70/30 blends. For the 30/70 blend, this model describes the data much closer than Palierne model and a little deviation occurs at low frequency. The comparison between the two models’ fitting results indicates interaction among dispersed droplets should be considered.