Flow-induced crystallization in poly-1-butene: the shish-kebab transition

In this work, flow-birefringence measurements have been performed to monitor the orientation development during application of high shear flow in undercooled polymer melts. It is demonstrated that a critical shear rate and a critical shear strain are required in order to form strongly oriented shish-kebab structures. After reaching such critical conditions, the crystallization kinetics - measured both by means of birefringence as well as transmitted intensity measurements - is drastically increased. The results generated in this work suggest that Janeschitz-Kriegl's [1] hypothesis about the need for a specific amount of work required to form shish-kebab structures is valid, at least for the conditions investigated.