Drawn fibrillar morphology

Drawn fibrillar morphology (developed when a spherulitic polymer is stretched below its melting point and the original lamellar crystallites are fragmented and rearranged into an oriented fibrous structure) (29)... 

What is drawn fibrillar morphology What is vitrification ... 

Hierarchical fibrillar model [80] This model was proposed for drawn TLCP fibers. They are composed of bundles of macro fibrils (5 p,m), fibrils (0.5 (Jim), and micro fibrils (0.05 p.m) in a hierarchical order (see Figure 8.17). This type of highly oriented fibrillar morphology is also found in the inner skin region of the injection-molded parts, as illustrated in Figure 8.18. 

In a different study, gel-drawn ultrahigh molecular weight PE was analyzed by SFM. The images showed different well-defined levels of the underlying fibrillar morphology (132). These include bundles of microfibrils (diameter between 4 and 7 /um), microfibrils (diameter between 0.2 and 1.2 / m), nanofibrils, and regular chain patterns on the molecular level (Fig. 19). 

Much has been written about fibrillar morphology, and several morphological models have been advanced to explain their observed features and physical properties. The vast majority of this research has centered on high density polyethylene, often drawn at temperatiu es substantially above ambient that favor high draw ratios. The various morphologies proposed may be rationalized into the hierarchy of stractures illustrated in Figure 3, which incorporates the most important features reported by different authors [9,10,12-17]. 

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