Stress-strain curves polyurethane elastomer

FIG. 11 Stress-strain curves for (a) a pristine polyurethane elastomer (b) a polyurethane-clay nanocomposite prepared from organomontmorillonite (5 wt%). (From Ref. 66.)... 

Figure 1. Stress-time data from stress-strain curves measured in simple tension at 30°C on the LHT-240 polyurethane elastomer at seven extension rates, A from 9.4 X t° 9.4 min 1. Key 0,9, stress as a function of time ( — 1)/X, at the indicated values of strain, ( — 1).

Figure 4. Stress-strain curves for the TIP A polyurethane elastomer measured at the indicated temperatures at an extension rate of 0.94 min 1. Arrows indicate...

Atomic force microscopy and attenuated total reflection infrared spectroscopy were used to study the changes occurring in the micromorphology of a single strut of flexible polyurethane foam. A mathematical model of the deformation and orientation in the rubbery phase, but which takes account of the harder domains, is presented which may be successfully used to predict the shapes of the stress-strain curves for solid polyurethane elastomers with different hard phase contents. It may also be used for low density polyethylene at different temperatures. Yield and rubber crosslink density are given as explanations of departure from ideal elastic behaviour. 17 refs. 

The tensile stress-strain deformation pattern for polyurethane elastomers is similar to those of other elastomers, and Fig. 13.1 shows typical curves for urethane elastomers of different hardness. Typically, for elastomers, the shape of the curve changes with increasing deformation so that elastic behaviour over the full stress-strain range cannot be defined simply by Young s modulus. Figure 13.2 shows a stress-strain curve at low strain values. This curve can be described by the general equation... 

Fig. 13.1. Typical stress-strain curves for urethane elastomers of different hardnesses. (Source P. Wright A. P. C. Gumming, Solid Polyurethane Elastomers. Maclaren Sons, London, 1969.)...

This high load-bearing capacity in compression is also exhibited in shear. Figure 13.5 shows the shear stress-strain curves for a series of urethane elastomers. It is important to emphasize that polyurethanes are elastomers even at very high hardness values whereas conventional elastomers have lost a considerable amount of elastic properties at the hardness regions of greater than 75 IRHD. 

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