Polyethylene fiber morphology

In several cases the formation of a special morphology imparts mechanical properties to "simple" macromolecules which hitherto have only be obtained with "exotic" polymers (e.g. high strength polyethylene fibers). 

Ethylene polymerization on planar silica-supported catalysts based on bis(imono)pyridyl complexes in solution produces polyethylene films with a uniform thickness. Upon drying, the films polymerized in toluene at room temperature break into islands which are connected by stress fibers. This island-fiber morphology is formed due to the shrinkage of the polymer film after the evaporation of the solvent which is trapped into the polymer film during polymerization. 

Lacroix F V, Loos J and Schulte K (1999) Morphological investigations of polyethylene fiber reinforced polyethylene. Polymer 40 843-847. 

Chen W, Fu Y, Wnnderhch B, Cheng J. The morphology of gel-spun polyethylene fibers, investigated by sohd-state 13C NMR. J Polym Sci B 1994 32 2661-2666. 

White, J.L., Dharod, K.C., Clark, E.S., 1974. Interaction of melt spinning and drawing variables on the crystalline morphology and mechanical properties of high-density and low-density polyethylene fiber. Journal of Applied Polymer Science 18, 2539—2568. 

Litvinov, V.M., Xu, J., Melian, C., Demco, D.E. MoUer, M. SimmeUnk, J., Morphology, chain dynamics, and domain sizes in highly drawn gel-spun ultrahigh molecular weight polyethylene fibers at the final stages of drawing by SAXS, WAXS, and IH solid-state NMR. Macromolecules 44, 9254-9266 (2011)... 

Figure 15.20 Interpretation of the morphologies in polyethylene fibers (a) very low speeds (<10 m/min) spherulites (b) low speeds (50 m/min) Keller I model (c) intermediate speeds (100-200 m/min) skin-core structure (d) high speed (556 m/min) Keller II model [73, 76].

The two-phase morphologic structure has also been observed in the electron micrographs of polyethylene films and fibers obtained by orientational crystallization16 in which the amount of ECC was approximately 15 to 20% (the fraction of ECC in Porter s samples47 was 17 to 25%). 

Morpholine chromate, molecular formula, properties, and uses, 6 562t Morphology. See also Structure of carbon fibers, 26 737-739 of high density polyethylene, 20 162 of polymer blends, 20 356 of polymer colloid, 20 386-388 of PVC particles, 25 658-661, 661-663, 664-665... 

By variation of the conditions of crystallization (see Sect. 1.3.3.3) polyethylene can be obtained either as folded lamellae, as extended chain crystals (high strength fiber), or as so-called shish kebabs (fibrils with a morphology similar to cellulose). All these variants differ in properties. 

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).]...

Guo, G. Wang, K.H. Park, C.B. et al. Effects of nanoparticles on the density reduction and cell morphology of extruded metallocene polyethylene/wood fiber nanocomposites. J. Appl. Polym. Sci. 2007, 104, 1058-1063. 

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