Formation shish kebab, mechanism

When polymers are crystallized under flow (stirring, extensional, etc.), the ubiquitous morphology [23] is the shish-kebab structure, consisting of central core (shish) surrounded by lamellae (kebabs) attached along the shish. What is the underlying mechanism behind the formation of shish-kebab stmcture ... 

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... 

This is a possible scenario but too bold at the moment. We need more data to conclude the formation mechanism of the shish-kebab structure. 

New Insights on the Molecular Mechanism of Shish-Kebab Formation... 

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. 

The use of Small-Angle Neutron Scattering (SANS) has been exponentially increasing for the study of polymers, largely of elastomers and nanopolymers, for the last 40 years [198]. Matsuba et al. [199] worked on an isotropic blend of deuterated PE and hydrogenated polyethylene (HPE 3 wt%) during uniaxial drawing at 125°C to understand the formation mechanism of the shish kebab from the isotropic film. In the early... 

SCORIM results in substantial enhancement of the physical properties of iPR The enhanced properties are related to the formation of shish-kebab morphology, and hence the high levels of molecular orientation that result from the application of macroscopic shears to a solidifying melt in a mold cavity. In this chapter, SCORIM technology is first described, and then relationships between processing conditions and mechanical properties are discussed, including a discussion on shish-kebab morphology, orientation and the occurrence of 7 phase in processed iPP. 

Fig. 61 Cartoon presenting the mechanism of wax crystallization on polymer templates. According to the experimental findings such a mechanism yields multiscale structures evolving hierarchically with decrease in temperature a the single coil stage b the formation of polymer rods with modulated density (alternation of crystalline and amorphous sequences along the rod axis) c the shish-kebab-like morphology formed by correlated polymer-wax plates templated by the initial polymer rods d a detail of the polymer-wax common plates, basically the same structure as that shown in Fig. 55. At lower temperatures and high wax content the wax surplus fills the space between the platelets and transforms the shish-kebab into large-scale one-dimensional object...

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