Semicrystalline polymers crystallization under flow

In the formation of crystals, polymer chains fold back and forth to form the crystalline lamellae. The crystalline lamellae and the amorphous phase are arranged in semicrystalline morphological entities, ranging from a micron to several millimeters in size. The most common morphologies that can be found in injection-molded polymers are spherulites, which usually form under quiescent conditions, and shish-kebab structures, which may appear under shear flow [see, for example, Eder and Janeschitz-Kriegl (1997), Zuidema et al. (2001) and Janeschitz-Kriegl (2009)]. 

While crystallization of polymers in the absence of deformation is conceptually simpler, most polymers in industrial practice are solidified under the influence of deformational flow fields. The consequences of such fields are far from trivial, giving rise to strikingly different crystal sizes, orientations, and semicrystalline morphology these effects are dealt with in greater detail in Chapter 14 and Chapter 15. The shish-kebab morphology observed during crystallization of PE in uniaxial flow is one such well-known distinction. Another is the amplification of nucleation density, by as much as five orders of magnitude for a modest input of work of... 

---