The effect of long chain branches on the shear flow behavior of polyethylene

The effects of long chain branching (LCB) on the viscosity and first normal stress coefficient of metallocene polyethylene (mPE) are described. LCB in creased the zero shear viscosity and the susceptibility to shear thinning. The first normal stress coefficient increased with degree of LCB at all rat es. The materials with LCB followed the Cox-Merz rule and the Gleissle mirr or relations while the linear material followed only the Cox-Merz rule. The se results indicate that the behavior of long chain branched mPE in simple shear can be predicted using only linear viscoelastic properties. (C) 2001 The Society of Rheology.