Melt spinning morphology development

Fig. 14.5 Morphological model of structures developed in as-spun HDPE. Take-up velocities are (a) very low (b) low (c) medium and (d) high. [Reprinted by permission from J. E. Spruiell and J. L. White, Structure Development during Polymer Processing Studies of the Melt Spinning of Polyethylene and Polypropylene Fibers, Polym. Eng. Set, 15, 660 (1975).]...

A cartoon of this model of morphology and molecular chain topology development in melt spinning of PET is shown in Figure 1.6. 

FIGURE 1.5 Morphology development in melt spinning as a function of key spinning parameters. 

FIGURE 1.6 A cartoon of morphology development in PET melt spinning. 

Finally, the manner in which individual molecules crystallize depends on the nature of the polymer molecule and the conditions under which crystallization takes place (see Fig. 5.18). It is worth noting at this point the work of Dees and Spruiell (1974) concerned with the structure development during melt spinning of HDPE fibers. Figure 9.9 presents their morphological model based on crystallite orientation factors and some other information. At low take-up speeds... 

In previous paper [8], we reported that a small amount of PP could obviously decrease the orientation of ethylene butene copolymer (EBM) in melt spinning. In this study, the phase morphology development of PP/EBM blends in extrusion and melt spinning is studied. The dispersed PP droplets were also found to form encapsulation layer in both high speed extrusion and melt spinning. The encapsulation phase morphology was found to affect the birefringence of the blends. 

Phase morphology development of polypropylene (PP)/ethylene butene copolymer (EBM) blends in both extrusion and melt spinning was studied. It was found that in the blend with dispersed PP phase, with the increase of extrusion or melt spinning speed PP droplets were first stretched into fibrils, and then the fibrils began to merge together at die wall, and at last a smooth PP layer was formed surrounding the extrudates or filaments. 

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