Lamellar and Spherulitic Morphology of the Zigzag Forms

Different morphologies can be obtained, depending on the crystallization conditions and on the crystalline forms. From the melt, SPS crystallizes according to a spherulitic morphology. Two different types of spherulites are observed sheaf-like spherulites with a fibrosity of a few micrometers, and round spheruhtes, which are 50 pm in diameter. They all show positive birefringence and have the same isothermal radial growth rate [66,67]. 

Cimmino et al. [68] proved by optical microscopy that the growth dimension of SPS spherulites is very sensitive to crystallization temperature and time. 

Sun and Woo [69] showed the optical microscopy results for SPS melt-crystalhzed at different temperatures. At lower temperatures polygon-shaped spherulites with an average size of 20 pm are observed. As melt crystallization temperature increases, the spheruhtes became coarser and turn to a sheaf-like pattern. 

Under appropriate thermal treatments SPS samples were prevalently crystallized into P -crystal modification, as revealed by WAXD. Lamellar morphology and thickness of these samples, melt-crystallized at various temperatures, were studied by Wang et al. [71] using TEM and small-angle X-ray scattering (SAXS). 

In a successive study of Wang et al. [72], SPS samples melt-crystallized into neat a hexagonal and P orthorhombic modifications were thoroughly prepared at various temperatures for extensive morphological studies. The 

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