Dielectric properties of the composite system polyurethane - sodium chloride
article
The dielectric properties of the composite system polyurethane-sodium chloride have been measured at frequencies between 10-4 Hz and 3-10 5 Hz in the temperature range from -150 °C up to +90 °C. Three dielectric loss mechanisms have been found, they are indicated by α1, α2 and β. The activation energy of the α1-transition is 35 kcal/mole, that of the β-transition 6.7 kcal/mole. The α2-loss peak was only observed at frequencies of 10-3 Hz and higher, forming one broad peak with the α1-loss peak at lower frequencies. In the composite materials, the β- and α2-loss peaks measured at fixed frequencies were found at the same temperature. The α2-loss peak, however, was shifted to a lower temperature, due to the sodium chloride filler. Comparison of experimental data of ε′ and tan δ with theoretical predictions concerning the dielectric properties of composite systems showed only partial agreement. The difference mainly consisted in. the temperature shift in the tan δ-peak of the α1-transition.
TNO Identifier
280804
DOI
https://dx.doi.org/10.1007/BF01973492
ISSN
00354511
Source
Rheologica Acta, 9(2), pp. 299-305.
Publisher
Steinkopff-Verlag
Pages
299-305
Files
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