Rheological Properties Related to Extrusion of Polyolefins

Rheological properties related to the extrusion of polyolefins are shear viscosity, elongational slip velocity and their temperature- pressure-dependencies. These measured in rheology lab mainly via a parallel-plate rheometer capillary rheometer. Then appropriate rheological models have be used account for all these properties. Such either viscous (e.g., Cross model) or viscoelastic K-BKZ model). The latter gives best fitting experimental data offers excellent results numerical simulations, especially flows. Wall effects also found by rheometric Modeling flows should make use that take into effect various parameters, including stress, molecular characteristics, temperature pressure on velocity. In this paper importance discussed.