| Abstract: | The melt rheological behaviour of three homologous HDPE-series, differing substantially in molecular weight distribution and each encompassing a broad molecular weight range, was investigated. The viscoelastic properties were measured by means of a sandwich-type creep rheometer and capillary viscosimeters. The zero shear viscosity is found to be proportional to the 3.6 power of the weight average molecular weight. The shear stress dependence of viscosity is related to the molecular weight distribution and is not influenced by molecular weight. The elastic behaviour (shear compliance) is also only effected by molecular polydispersity. This normal behaviour of PE is easily obscured by long chain branching. Few long chain branches cause considerable deviations of the rheological properties. |
