Elongational drawing

Figuie 1 (a) Effect of elongational drawing on the elastic modulus ( ) of extruded PP/LCP blends, (b) Morphology of highly drawn PP/LCP 80/20 blend (LCP = Vectra A950, Hoechst Celanese) [4]. 

LDPE Low-density polyethylene s Elongation (draw) ratio stretching... 

Application Title (dtex) Tenacity (cN/dtex) Elongation (%) Draw tension (N/dtex) Hole counts... 

The distribution of fillers across the membrane is vital to determine the morphology and performance of the composite hollow fibers. Jiang et al. [91] reported that (1) the shear rate within the spinneret, (2) the die swell at the outlet of the spinneret, and (3) the elongation draw at the air-gap region were the factors affecting the filler distribution in the mixed-matrix composite hollow fibers, whereas Xiao et al. [92] observed that a high elongation draw ratio can radially displace the fillers toward the bore and shell side of the composite hollow fibers. 

The ratio of stress to strain in the initial linear portion of the stress—strain curve indicates the abiUty of a material to resist deformation and return to its original form. This modulus of elasticity, or Young s modulus, is related to many of the mechanical performance characteristics of textile products. The modulus of elasticity can be affected by drawing, ie, elongating the fiber environment, ie, wet or dry, temperature or other procedures. Values for commercial acetate and triacetate fibers are generally in the 2.2—4.0 N/tex (25—45 gf/den) range. 

In the coupled process (Fig. 7c), the draw ratio, which affects the tenacity and elongation, lowers with increasing spinning speed. As draw ratio is increased, tenacity and initial modulus increase and elongation decreases. 

It is more convenient to use the procedure of the first kind for higher drawn fibers (over 350% of elongation) and the second procedure for fibers of smaller drawing. The value of the angle of inclination of the texture depends on the magnitude of the drawing applied. As a result of the investigations of one of the authors... 

The factor having the strongest effect is the elongation imparted in the process of production stretching. Second, the overall orientation is affected by the stretching rate. For the same draw ratio, the overall orientation grows with an increase in the stretching rate. The effect of the draw ratio on the value of Hermans function of orientation is illustrated by the values of/o, established by the authors and depicted in Table 7. 

Thermoplastic polymers subjected to a continuous stress above the yield point experience the phenomenon of cold-drawing. At the yield point, the polymer forms a neck at a particular zone of the specimen. As the polymer is elongated further, so this neck region grows, as illustrated in Figure 7.7. 

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