Measurement and modeling of planar and uniaxial extensional viscosities for LDPE polymer melt

In this work, novel patent pending rectangle and circular orifice dies have been used in order to determine planar and uniaxial extensional viscosities for extrusion coating LDPE through entrance pressure drop determination on conventional twin bore capillary rheometr. It has been revealed that the uniaxial extensional viscosity/uniaxial extensional strain hardening is higher in comparison with the planar extensional viscosity. It also has been found that recently proposed non-Newtonian fluid model [M. Zatloukal, Annual Technical Conference - ANTEC, Conference Proceedings 1, 92-96, 2011] can described the measured rheological data reasonably well