The study of the instability phenomena of polymer melts in capillary flows is of great technical relevance since, during an industrial die forming operation, these instabilities can give origin to a transition from a defect-free to a highly-defective extrudate. In this work, the instability phenomena exhibited in capillary flow by a blow moulding grade of high-density polyethylene (HDPE) were analyzed. In particular, by means of a capillary rheometer, which mimics polymer extrusion, the effects of specific extrusion parameters (temperature and imposed flow rate) on the oscillating flow, that takes place when "stick-slip" instabilities occur, were investigated.
Oscillating flow in capillary dies for a HDPE melt: effects of extrusion parameters
BALDI, Francesco;RICCO', Theonis
2010-01-01
Abstract
The study of the instability phenomena of polymer melts in capillary flows is of great technical relevance since, during an industrial die forming operation, these instabilities can give origin to a transition from a defect-free to a highly-defective extrudate. In this work, the instability phenomena exhibited in capillary flow by a blow moulding grade of high-density polyethylene (HDPE) were analyzed. In particular, by means of a capillary rheometer, which mimics polymer extrusion, the effects of specific extrusion parameters (temperature and imposed flow rate) on the oscillating flow, that takes place when "stick-slip" instabilities occur, were investigated.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
