Rheological properties and molecular structure of polymer melts

An overview is given on relations between some features of the molecular structure of polymers and their viscous and elastic properties in the molten state. Moreover, it is discussed how the elongational behaviour of polymer melts can be affected by molecular parameters. Besides the effects of molar mass and molar mass distribution, more recent results on the influence of long-chain branching on rheological properties are presented. While relations between rheology and processing are addressed only shortly, the applications of the rheological investigations with respect to a molecular characterisation and to the detection of small amounts of long-chain branches, in particular, are discussed in more detail. Although obtained on materials of a rather simple molecular structure, the results described in this short review have the potential to be used for other polymeric materials in the field of soft matter, too.