Dynamic mechanical storage spectra

Figure 8. The high-temperature dynamic mechanical spectrum of Halthane 88-2 shows that some further curing is occurring above 100°C because both storage and loss modulus increase over a...

FIGURE 13.24 (a) The dynamic mechanical spectrum for polyfethylene terephthalate) (PET) showing the storage modulus and tan 5 as a function of temperature, (b) The dielectric (storage and tan 5) behavior for PET in comparison with the mechanical response. (From Wetton, R.E. et al.. Inti. Lab., March, 1986. Figure 13a and Figure 13b, p. 60. With permission from International Laboratory.)... 

At acoustic frequencies, the attenuation goes through a maximum determined by the spectrum of relaxation times in the polymer hence dynamical mechanical analysis can be performed by scanning over a wide frequency range, typically 10 —lO Hz. An example of the technique is sonic DMA of PVC [54] which shows that the shear modulus increase monotonically with frequency, while the longitudinal or extensional modulus displays the transition associated with Tp. The ratio of the loss and storage moduli, or tan delta obtained via DMA can be related to the absorption coefficient through the equation [2] ... 

Figure 19 (a) Dependence of storage (S ) and loss (S") modulus of a bottle brush with polymethacrylate backbone with DP = 3500 and poly(nBA) SC with DP = 30. (b) Dynamic mechanical spectra of a cross-linked sample of polymer shown in spectrum (a). 

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