This work examined the rheological properties for a series of highly branched polyethylene

samples prepared with a Pd-diimine catalyst system. It was revealed that the polymers produced at low pressure (0.2 and 1 atm) and higher temperature (35 °C) exhibited rheological behavior characteristic of hyperbranched polymers. The samples had very low

viscosities and showed Newtonian flow behavior due to the absence of chain entanglements. The change of chain topology from hyperbranched to linear led to much higher viscosity and non-Newtonian flow behavior due to chain entanglements.