Effect of die wall cooling or heating on extrudate swell

Abstract A general purpose finite element program was used to study polymer extrudate swelling. It is shown that viscosity variations due to externally applied cooling or heating have a significant influence on the swelling ratios of axisymmetric and planar extrudates. The effect is more pronounced at high Peclet and Weissenberg numbers. Swelling due to thermal effects and swelling due to viscoelasticity are not additive because of interrelations between the various mechanisms.