Physical Mechanism of Stick-Slip Behavior in Polymer Melt Extrusion: Temperature Dependence of Flow Curve

抄録

The flow instability in a polymer liquid extruded from a die has been discussed on its temperature dependence, based on a modeling of the behavior by a statistical stick-slip model of a group of springs. The present experimental results of polyethylene melt showed the shift of an N-shaped flow curve to lower shear rate with decreasing temperature, which approaches the melting point of polyethylene crystals. This result is consistent with the microscopic modeling of the flow instability with the disentanglement of the chain in the bulk under high shear rate. The shift of flow curve with temperature explains the existence of the temperature window with minimum applied pressure under constant speed found by Keller et al.