Use of the dielectrometer for the determination of the complex dielectric constant in the microwave region in organic high polymers at various temperatures
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Titel:
Use of the dielectrometer for the determination of the complex dielectric constant in the microwave region in organic high polymers at various temperatures
Beschreibung:
<jats:title>Abstract</jats:title><jats:p>A commercial type dielectrometer has been utilized for determining the complex dielectric constant of insulating materials as a function of temperature. For low‐temperature measurements, modifications of the apparatus have been made, by which the lower section of the guide, containing the specimen, is insulated from the upper section by means of a Teflon disk, in order to permit measurements under vacuum without difficulties arising from moisture condensation. Taking into account the modifications made, relations between the experimentally measured quantities and the complex dielectric constant have been elaborated, and error analysis made, and best conditions to perform experimental measurements determined. For high‐ and medium‐loss materials, in the low‐temperature range, an accuracy of the order of 1% in ϵ′ and of 10% in ϵ″ have been calculated. Better results can be obtained for measurements at high temperature. The apparatus performance and the accuracy of measurements have been checked through measurements of the complex dielectric constant of different polar polymers at frequencies of the order of 9 × 10<jats:sup>9</jats:sup> Hz, at temperatures between −150 and 200°C. The experimental results are in good agreement with literature data derived from experimental measurements with other techniques and with the behavior expected on the basis of the results from radiofrequency measurements through considerations of molecular mobility in relation to molecular structure.</jats:p>