Dielectric response of fibrous polyethyleneterephtalate

The effect of the electric periodic field on the dielectric parameters (relative dielectric permeability and dielectric tangent of losses) of fibrous polyethyleneterephtalate (PET) different structures was studied. The analysis of dielectric relaxation spectra has been performed in the frequency range from 90 kHz to 3 MHz, while the sample was heating from 120 to 355 K. In this range of measurements, β relaxation is observed and the activation energy of molecular motion is established. Through a comparison of obtained results, a relationship is noted between dielectric parameters and structural properties of a sample. It is observed that samples whose yarn is obtained from short fibre have lower value of dielectric parameters than samples with monofilament and multifilament yarn. Samples with higher values of volume fraction of fibres show higher values of dielectric parameters. In room conditions a comparison between dielectric parameters of the samples and a sample with incorporated electrically conductive threads has been performed. The dielectric response of the tested fibrous PET is comparable with the dielectric response of other PET – based structures.

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► Fibrous PET different structures were investigated by dielectric spectroscopy.
► The analysis has been performed in the wide frequency and temperature range.
► β relaxation is observed and activation energy of molecular motion is estimated.
► Dielectric parameters are higher in samples with higher volume fraction of fibres.
► The influence of added electrically conductive threads was tested.