Molecular stress function theory and analysis of branching structure in industrial polyolefins

Despite substantial progress in analytical techniques for polymer characterization, a realistic picture of branching structure in industrial polymers still remains at large. Using a number of assumptions, structure-based constitutive models can distinguish between linear and branched structures in a qualitative sense. More detail on branching architecture, such as the number and length of side chains, the sequence in which they exist on the backbone and their contribution to polymer chain relaxation is more or less unknown. In the current study, elongational behavior of four commercial polyolefins is compared using the predictions of the MSF (molecular stress function) theory. The results will then be used to analyze the branching in a group of strain-hardening polypropylenes synthesized using single site catalyst.