Linear low density polyethylenes and their blends: Part 5 extensional flow of LLDPE blends

The uniaxial extensional flow at 150°C of two series of blends: I. LLDPE/LLDPE and II. LLDPE/LDPE was examined in full range of concentrations as well as that of accessible in the rheometer strains and strain rates. It was concluded that Series‐I blends containing different LLD‐type polymers are miscible. Their properties can be predicted on the basis of molecular weight and molecular weight distribution. By contrast, excepting low concentration limits, blends of Series‐II are immiscible. Both series show strain hardening, due to higher values of the maximum strain at break. Series‐II seems to be superior (under the test conditions). The stress growth function in shear, computed from the frequency relaxation spectrum, provided a good prediction of the linear viscoelastic component of the stress growth function in uniaxial extension.