Experimental investigation of flow induced molecular weight fractionation during extrusion of HDPE polymer melts

In this work, two different HDPEs with virtually identical number, Mn, and weight, Mw, average molecular weights were investigated from rheological as well as die drool phenomenon point of view. It has been revealed that long-chain branching, low polymer melt elasticity and shear viscosity significantly reduce die drool phenomenon at the die exit region. It has been concluded that die drool phenomenon of HDPE polymer melts can be explained by the flow induced molecular weight fractionation.

► Long-chain branching, low polymer melt elasticity and shear viscosity significantly reduce die drool phenomenon during HDPE extrusion.
► Die drool material represents low molecular weight fraction of HDPE.
► HDPE die drool onset is initiated at the slip-stick flow regime.