Investigation of Extensional Flow Behavior of Polyethylene Melts through Birefringence by using Extrusion Cross-slot Die
Academic Journal of Polymer Science - Juniper Publishers Abstract Flow parameters of polymers melt under steady state condition in shear are required to assess flow behaviour of the molten material in the die or downstream operations. Very often this is not sufficient to have a full understanding of the polymer processability, and additional information of flow response in extension is also needed. In this paper, the extensional properties of two molten polyethylene have been investigated by measuring stress response when a high extensional deformation is applied in a cross-slot die. Flow induced birefringence analysis and stress-optical rule are applied to determine rheological properties. Two polyethylene’s with similar rheology in shear but different molecular structure (...