抄録
In order to establish the relationship between the distribution function Fτ(τ) of relaxation time τ and the shape and the characteristic parameters of dynamic loss tangent (tanΔ)-temperature (T) curves, theoretical equations representing tanΔ-T curves are derived; seven functions given by Fτ(τ)=kn'τn' and three functions given by triangles. WLF and Arrhenius types are assumed for temperature dependence of τ. On the basis of these theoretical equations, tanΔ-T curves are numerically calculated. In the case of n'_??_0, the peak value of tanΔ-T curve, (tanΔ)max, peak temperature Tmax and the ratio of half value width ΔT1/2/ΔT1/2 (s) (the suffix s indicates the system composing of a single relaxation time) depend on those factors as the average relaxation time τ, Fτ, the total number of Maxwell elements in a system N, the ratio of elastic modulus before and after relaxation α, and the minimum relaxation time τl in Fτ(τ). In the case of n'_??_-0.5, a significant shoulder is observed on tanΔ-T curves in the lower temperature region than Tmax. The necessary condition to have this shoulder is (tanΔ)max_??_3.5/(n'+3)4 and N_??_√<10>, The tanΔ-T curve (especially, ΔT1/2/ΔT1/2 (s) ), measured in the temperature range in which appears the dynamic absorption arising from microbrownian movement of polymer segments in amorphous region of semi-crystalline polymers (αa), is remarkably different from that calculated by using the above mentioned functions for Fτ(τ). Contrary to this, tanΔ-T curves determined experimentally in the temperature range of αa absorption of amorphous polymers are in good agreement with those calculated by using n'=-2-0. In the actual experiment, no shoulder, is observed on tanΔ-T curves for both amorphous and semi-crystalline polymers.
