Polyurethane Stress-strain curves

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. 

Figure 10.4 Stress-strain curves for control and modular polymers. The curve in the bottom (—) is for the polyurethane (PU) made fiom poly(tetramethylene glycol) and...

In practice, up to 90% of polyurethanes are used in compression, a few percent in torsion, and very little in tension. There is considerable data on the tensile stress against tensile strain (elongation) for polyurethanes. Most polyurethane specification sheets provide this data. Figure 7.3 and Figure 7.4 show typical stress-strain curves for both polyester and polyether polyurethanes. 

Hygroscopic Hysteresis hydroxyl content of 1.0 g of polyol. A material that absorbs moisture readily. The ability of polyurethane to absorb and dissipate energy due to successive deformation and relaxation. A measurement of the area between the deformation and relaxation stress-strain curves. 

Figure 15.30. Stress-strain curves for glass bead filled polyurethane with different concentrations of glass beads. [Data from Vratsanos L A, Farris R J, Polym. Engng. Sci., 33, No.22, 1993, 1458-65.]...

Figure 1 shows stress-strain curves for the commercial polyether polyurethane and for PU-13, made from methane diphenyl dllsocyanate (MDI), butane diol (BD), and polytetramethylene oxide diol of molecular weight, 2000 (PTMO 2000). There is little difference in stress values for aged and imaged polymers. 

Figure 9.15 Stress/strain curves of aqueous polyurethane/urea dispersion films...

Fig. 13 Stress-strain curves for nanocomposites of a thermoplastic polyurethane (TPU) filled with different layered compound at loading levels of 5 weight percent (wt%) and 20 wt%. (Reproduced with permission).

SPI, soy fibre, and corn starch together with 0 0 per cent polyetho- polyol were also incorporated into a flexible polyurethane foam formulation. Stress-strain curves of the control foam and foams containing 10-20 per cent biomass material exhibited a considerable plateau stress region, but not for foams extended with 30—40 per cent of them. An increase in the hiomass content produced an increase in the foam density, whereas an increase in the initial water content produced the opposite effect. Foams extended with 30 per cent SPI, as well as those extended with 30 per cent soy fibre, displayed considerably higher resilience values than all other extended foams. The comfort factor increased by increasing the biomass content, and foams containing 10—40 per cent biomass showed significantly lower values in compression-set than the control foam [86]. 

Fig. 3 Effects of water on an amorphous polyurethane SMP. (a) Tg as a function of the weight fracture of moisture of the polymer, (b) Stress-strain curves after immersion in water for (1) 0 h, (2) 2 h, (3) 24 h, (4) 162 h, (5) 432 h, and (6) 768 h. Modified from [61], Copyright 2004 with permission from the Institute of Physics and lOP Pubhshing. http //dx.doi.Org/10.1088/0964-1726/13/l/022...

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. 

Figure 6.4 Stress—strain curves of polyurethanes synthesised from poiy(caproiactone) dioi, 1,4-butanediisocyanate, and different chain extenders based on L-iysine ethyi ester (K-BC2000) N-Boc serinol (NS-BC2000) H-Ala-Ala-NH-(CH2)4-NH2) (A-BC2000) and (1,4-cyclohexane dimethanol) (C-BC2000).

Fig. 23. Stress-strain curves for several castor oil (CO), polyester (PE), polyurethane (PU), and polystyrene network (PSN) materials. A COPEN B COPEUN C COPUN D 40/60 COPEN/PSN E 40/60 COPEUN/PSN F 40/60 COPUN/PSN and G 40/60 COPUN/PSN.

Fig. 2 Stress-strain curves for various segmented polyurethane-urea copol3rniers indicating the dependence of tensile behavior on the soft segment molecular weight. (1) PTMO-2000-MDI-31-DCA, (2) PTMO-IOOO-MDI-31-DCA, and (3) PTMO-650-MDI-31-DCA.

Fig. 16 Stress-strain curves for nanocomposites consisting of solvent-exfoliated graphene in a polyurethane matrix with different loadings of graphene (weight %). (After ref 180.)... 

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