Abstract
Viscoelastic behavior of poly (bisphenol-A carbonate) above the glass transition temperature is studied by a creep test. In the primary dispersion region, the retardation spectrum increases with increase of retardation time with a slope of 1/2 in a doubly logarithmic plot as predicted by the Rouse theory, and then reaches a maximum. The molecular weight between entanglements is estimated as 2300 from this maximum value. The temperature dependence of retardation times obeys the WLF equation. The local mode dispersion below the glass transition temperature is studied by use of several dynamic methods. Dielectric measurement is made for comparison. The activation energy is obtained as 11 kcal/mode. Distribution of retardation times of the local mode dispersion is attributed to non-uniformity in force constant and friction coefficient to each molecular unit.
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