Master surfaces of viscoelastic functions in the reciprocal temperature-frequency space

Summary

Starting from EYRING's transition state theory it is demonstrated for systems obeying the superposition principle that the frequency shift factors of isotherm mastercurves of the viscoelastic functions as well as the temperature shift factors of the isochrone ones are unequivocally interrelated with the apparent activation energy of flow. The method for the evaluation of the activation energy from viscoelastic data is discussed, considering the moduli surfaces in the reciprocal temperature — frequency space. Experimental data prove the reliability of the approach. It is demonstrated that it is much more suitable to construct mastercurves as well as master surfaces in this way, because it is not necessary to apply measurements at low frequencies, which are unavoidable when the curves are constructed by empirical shift in the usual way.