Journal of Non-Newtonian Fluid Mechanics, Vol.165, No.5-6, 212-218, 2010
Extensional viscosity in uniaxial extension and contraction flow-Comparison of experimental methods and application of the molecular stress function model
Extensional viscosity of a low-density polyethylene was measured at three temperatures in uniaxial extension by Sentmanat Extension Rheometer, and in contraction flow using the Cogswell analysis. The molecular stress function model was applied to describe the experimental results. The achieved maximum values from uniaxial transient tests were in accordance with the ones obtained by Cogswell method at similar strain level, and the molecular stress function model was able to describe the experimental transient uniaxial extensional data. The steady-state extensional viscosity was not reached in the experiments. (C) 2009 Elsevier B.V. All rights reserved.
Keywords:SER;Cogswell analysis;Extensional viscosity;Contraction flow;Uniaxial extension;LOPE;MSF model