Rheology of column-fractionated ethylene/α-olefin copolymers prepared with metallocene catalyst

摘要

The viscoelastic properties of column-fractionated alpha-olefin copolymers made by metallocene catalysts were studied. The Effects of long chain branching on the rheological properties were investigated for fractions obtained from two types whole polymers which were produced using different catalysts. Fractions including polymer chains with long branches have long relaxation times. It was found that the long branching causes strong effects such as the molecular weight dependence on zero-shear viscosity. The Damping function of polymer fractions is similar to that of the unfractionaled polymer from stress relaxation experiments.