Flow-induced shish formation

Hashimoto T, Murase H, Ohta Y (2010) A new scenario of flow-induced shish-kebab formation in entangled polymer solutions. Macromolecules 43 6542-6548 Herrmann K, Gemgross O, Abitz W (1930) Zur Rontgenographischen Strukturforschung des Gelatinemicells. ZPhys Chem B10 371-394... 

The epitaxial growth and the formation of a shish-kebab stmcture were also investigated in high molecular weight iPP (HMW-iPP)/low-molecular-weight LLDPE (LMW-LLDPE) blends [21]. The formation of the initial crystallization precursor structure was investigated by using synchrotron WAXS/SAXS techniques at 130 and 140 °C. Shear was applied at temperatures above the cloud points of these blends, and therefore, the HMW-iPP chains could form a flow-induced crystalline stmcture in the blends only at 6 and 9 wt% of HMW-iPP LMW-LLDPE merely served as the amorphous matrix (Fig. 5.3). When the HMW-iPP... 

There are still hot ongoing debates about the formation mechanism of shish structures in the oriented flow field. Recently, Hashimoto and his coworkers proposed a new scenario for flow-induced phase transitions in polymer solutions to form the hierarchical structures of shish-kebabs (Hashimoto et al. 2010 Murase... 

Fig. 8.1. Schematic representation of flow-induced precursor structures at different stages (A) before shear, (B) formation of precursor structures containing linear nuclei (shish), (C) formation of shish-kebab morphology. (Reprinted with permission from [21])...

The rheo-SAXS study of the LMWPE/HMA PE blend has revealed several new insights into the molecular mechanism of shish-kebab formation at the initial stage of flow-induced crystallization. These insights can be summarized as follows. 

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