Relaxation spectroscopy of poly(vinylidene fluoride)

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Abstract
The relaxation spectra and their temperature dependence for the four relaxation processes in poly(vinylidene fluoride) found in the temperature range from −180°C to 130°C are determined by using stress relaxation measurement and complementary dielectric loss measurement. These relaxations are designated as α M , β, γ1 and γ2 in the order of descending temperature. A comparative study of the characteristics of the relaxations in poly(vinylidene fluoride) and poly(ethylene) shows that these relaxations in poly(vinylidene fluoride) correspond to the α2-, β-, γ1-and γ2-relaxations in poly(ethylene) respectively. Further, a slight loss process is found in poly(vinylidene fluoride) in the temperature range between the α M -region and the β-region and it is thought to correspond to the α1-relaxation in poly(ethylene). The temperature dependence of relaxation times for the β-relaxation is expressed by WLF equation and the glass transition temperature is estimated to be ca. −42°C.