Experimental investigation of die drool and slip-stick phenomena during HDPE polymer melt extrusion

Abstract

In this work, two slightly different batches of one commercial linear HDPE polymer melt were rheologically characterized and then extruded through two specially designed dies (annular and slit) in order to investigate die drool as well as slip-stick phenomena. Flow birefringence stress visualization inside the slit die was also performed. It has been revealed that lower elasticity and both shear and extensional viscosities reduce accumulated drool mass at the die exit face and also correlation between appearance and intensity of both slip-stick and die drool phenomena was discovered.