Draw ratio Poly

The film tube is collapsed within a V-shaped frame of rollers and is nipped at the end of the frame to trap the air within the bubble. The nip roUs also draw the film away from the die. The draw rate is controlled to balance the physical properties with the transverse properties achieved by the blow draw ratio. The tube may be wound as such or may be sHt and wound as a single-film layer onto one or more roUs. The tube may also be direcdy processed into bags. The blown film method is used principally to produce polyethylene film. It has occasionally been used for polypropylene, poly(ethylene terephthalate), vinyls, nylon, and other polymers. 

Fig. 9. Piezoelectric strain constant of uniaxially drawn poly(y-methyl L-glutamate) film (a-helical form) plotted against the angle 6 between draw-axis and stress direction. Draw-ratio = 2. Drawn after Fukada, Date, and Hirai [Nature 211, 1079 (1966)] by permission of Macmillan (Journals) Ltd.

Fig. 11. Complex piezoelectric strain constant (20 Hz), complex Young s modulus (30 Hz), and complex dielectric constant (1kHz) of uniaxially drawn poly(D-propylene oxide) film plotted against temperature. Draw-ratio = 1.5. Degree of crystallinity=40%. Drawn after Furukawa and Fukada [Nature 221,1235 (1969)] by permission of Macmillan (Journals) Ltd.

Fig. 25. Ratio of electrostriction constant to dielectric constant of roll-drawn poly(vinylidene fluoride) film (draw-ratio = 2.3) plotted against angle 0 between elongational strain and draw-axis. Drawn after Nakamura and Wada [J. Polymer Sci. A-2,9,161 (1971)] by permission of John Wiley Sons, Inc.

Fig. 28. Piezoelectric stress constant obtained from inverse piezoelectric effect and electrostriction constant of drawn and polarized poly(vinylidene fluoride) film plotted against temperature. Draw ratio = 7. Polarized at 90° C under the field of 400 kV/ctn for 3 hours. Frequency of applied voltage = 37.5 Hz. (Oshiki and Fukada, 1971) Broken line represents dielectric constant at 21.5 Hz for roll-drawn poly (vinylidene fluoride) film (Peterlin and Eiweil, 1969)...

An interesting example of the difference in drawing behaviour between amorphous and crystalline yam is the drawing of crystalline poly(ethylene terephthalate). It is often stated that crystalline PETP cannot be drawn. It is tme that the material breaks if drawn at a temperature of 80 °C, which is a drawing temperature normal for the amorphous polymer. Mitsuishi and Domae (1965), however, were able to draw crystalline PETP to a draw ratio of 5.5 at a temperature of 180 °C. 

Table 6. Extrusion conditions for the poly-(ether ester) C. Nominal draw ratio 4 (for sample description see Table 4) ...

Figure 12 shows the influence of the nominal draw ratio on the tensile properties for the poly(ether ester) C. The initial tensile modulus was nearly independent of the draw ratio. A higher strains the modulus increased proportionally to the draw ratio. As can be seen from Fig. 13, the effect of the extrusion velodty on the tensile properties was rather small. 

Fig. 9. Heat of melting of extrudates vs. supercooling for poly(ether ester)s. ( ) material C, (O) B, (A) A. Arrows denote the heats of melting of the isotropic samples prior to extrusion. Rate of extrusion 0.4 mm /s, nominal draw ratio 4 (for sample description see Table 4) ...

Figure 4. E -modulus (GPa) as a function of draw ratio for 20 mol% p-hydraxy benzoic acid modified poly(phenyl-l,4-phenylene terephthalate) (not listed in tables) fibers. Spinning temp. = 320°C.

Fig. 12. Stress-strain curves for poly(ether ester) C. Parameter nominal draw ratio. Initial sample length 25 mm, strain rate 1 mm/s, 25 °C. Rate of extrusion 0.4 mm3/s, extrusion temperature 180 °C (for sample description see Table 4)M)...

FIGURE 25. Intensity of parallel component of fluorescence, Iii, as function of orientation of sample in unUxially stretched poly(vinyl alcohol) film at draw ratios of (1), 1, (2) 1.08,... 

The poly (vinyl alcohol)-gold nanocomposites were finally drawn at 120°C up to a draw ratio (DR), defined as the ratio of the length before and after drawing, of 5. It is well known that the polymer molecules orient upon drawing, and it was evident from TEM images of thin sections of the drawn materials... 

TABLE 9.1. Absorption Maxima of Drawn Poly(ethylene)-Gold Nanocomposites (Draw Ratio 15) at Different Reaction Conditions and Different Angles (p Between the Polarization Plane of the Incident Linearly Polarized Light and the Drawing Axis of the Specimen"... 

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