Crystallization from the melt and growth of spherulites

Electron-microscopy studies of the morphology of spherulites grown from the melt revealed that they were made up of stacks of lamellae of thicknesses quite similar to those of the lamellae crystallized from dilute solutions (Fischer 1957). Since the level of crystallinity of the spherulites was considerably less than 100%, it had to be concluded that the lamellae were separated by an amorphous component, often of similar thickness to the crystalline lamellae, producing characteristic X-ray-diffraction signatures of an amorphous component. 

A final difficulty with the adjacent-reentry model was thought to be of a kinetic nature in that the reeling-in of long-chain molecules from the melt onto a growth face of a lamella was considered to be far too slow to account for the observed growth rates (Flory and Yoon 1978). 

Finally, to more specifically explore the nature of the amorphous component of spherulitic polyethylene and the nature of the fold surfaces of the lamellae, Hoffman and collaborators (Guttman et al. 1981 Guttman and di Marzio 1982) performed a probabilistic choice computation on whether molecules in the amorphous component undergo adjacent reentry, undergo non-adjacent reentry 

In conclusion we adopt an operationally useful model of spherulitic PE due to Hoffman et al. (1976) as depicted in Fig. 2.20, consisting of radially emanating 

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