Modulus-temperature curves for

Fig. 19. Generalized modulus—temperature curves for polymeric materials showing the high modulus glassy state, glass-transition regions for cured and uncured polymers, plateau regions for cross-linked polymers, and the dropoff in modulus for a linear polymer.

Figure 1. Modulus-temperature curves for various plastics...

Figure /. Modulus-temperature curves for pure and plasticized (30 wt. % dioctyl phthalate) polyvinyl chloride...

At sufficiently low temperatures a polymer will be a hard, brittle material with a modulus greater than lO N m (10 dyn/cm ). This is the glassy region. The tensile modulus is a function of the polymer temperature and is a useful guide to mechanical behavior. Figure I 1-8 shows a typical modulus-temperature curve for an amorphous polymer. 

For a polymer where crystallinity dominates its relaxation behavior, the situation is quite different. Figure 4-3 shows the 10-second modulus vs. temperature curve for such a crystalline polymer, polyethylene (PE). Included also in this figure is the modulus-temperature curve for polyvinyl chloride... 

Figure 17.3. Generalized Modulus-Temperature curves for engineering polymer blends for automotive applications combinations of high amorphous polymers with lower Tg crystalline polymers. Reproduced with permission from L. M. Robeson, in Contemporary Topics in Polymer Science, Vol. 6, Multiphase Macromolecular Systems , B. M. Culbertson, Ed., Plenum Press, New York, 1989.

Two polypropylene materials have densities 0.905 and 0.87 g/cm. Sketch the modulus-temperature curves for these materials on the same graph. 

Example 14.4 Figure E.14.4 shows the loss modulus-temperature curves for the two materials A and B. Select either A or B for use as... 

Fortunately for linear amorphous polymers, modulus is a function of time and temperature only (not of load history). Modulus-time and modulus-temperature curves for these polymers have identieal shapes they show the same regions of viscoelastic behavior, and in each region the modulus values vary only within an order of magnitude. Thus, it is reasonable to assume from such similarity in behavior that time and temperature have an equivalent effect on modulus. Such indeed has been found to be the case. Viscoelastic properties of linear amorphous polymers show time-temperature equivalence. This constitutes the basis for the time-temperature superposition principle. The equivalence of time and temperature permits the extrapolation of short-term test data to several decades of time by carrying out experiments at different temperatures. 

Figure 24 Typical modulus-temperature curve for an amorphous adhesive.

FIGURE 15.9 Illustration of the variation in the modulus-temperature curves for three types of polystyrene. 

Fig. 12.15 Modulus-temperature curves for two polyurethanes with different compositions. Note the two glass-transition temperatures for each polymer, corresponding to those of the hard and soft segments. (Adapted by permission of John Wiley Sons, Inc.)...

FIGURE 1. Idealized Modulus/Temperature Curves for Vlsco Elastic Polymers. 

Figure 5.6. Modulus-temperature curves for several polyurethanes in comparison with various classes of polymer (A) Schematic curve for a linear amorphous polymer (B) schematic curve for a crosslinked polymer (C) schematic curve for a semicrystalline polymer (D) poly(ester urethane),Estane 5740-100 (E) poly(ester urethane),Estane 5740-070. Note that the polyurethanes exhibit two distinct glass transitions. (Cooper and Tobolsky, 1966u.)...

Figure 5.2 Modulus-temperature curves for (a) polycarbonate, (6) polypropylene, and (c) generic thermoplastic and cross-linked materials. Part c was adapted from Ref. 6.)...

The effect of temperature on the mechanical response of the polymer-leather composites remains to be treated. In Figure 20 are shown the torsional modulus-temperature curves for the three... 

Fig. 19.10. Generalized modulus-temperatures curves for low (A), moderate (B), and high (C) molecular weight amorphous thermoplastic polymers.

Fig. 19.11. Modulus-temperature curve for a semi-crystalline polymer.

Fig. 19.12. Generalized modulus-temperature curve for an amorphous thermoplastic A) and for thermosets that are lightly (5) and highly (C) cross-linked.

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