Dielectric investigation of some woven fabrics

In this paper, we have investigated the temperature dependence of dielectric properties (relative dielectric permeabilities and dielectric tangents of losses) for woven fabrics of hemp, jute, flax, cotton, polyester (PES), cotton-PES mixture, and wool. The measurements have been carried out at a temperature range from -50 to 50 degrees C in the electric periodic field at a frequency 1 MHz in vacuum. For the same specimens, the values of the dielectric properties have also been measured at an air temperature of 21 degrees C and at relative humidities of 40%, 60%, and 80%. At different frequencies from 80 kHz to 5 MHz, the dielectric properties have been measured at a relative humidity of 40% and at a temperature of 21 degrees C. An investigation of the dielectric properties of woven fabrics can provide a better understanding of the relation between the dielectric properties of woven fabrics and the different raw material compositions, temperatures, relative air humidities, and frequencies for specimens. Hence, this investigation helps to improve textile material properties

Comparative study of the electrical and structural properties of woven fabrics

The application of woven fabrics as the substrate materials for electronic products causes the need to examine their electrical properties at various external effects. This paper presents the results of electrical properties of the fabrics of cotton, cotton/polyethyleneterephtalate (PET) and PET. Dielectric loss factor and dielectric permeability were analyzed in a wide range of temperatures and frequencies. Relaxation peak which appears in this measuring region was identified as the secondary beta-relaxation. At different frequencies the dielectric permeability has been analyzed at a different relative humidity at room temperature. At the higher values of relative humidity with the increase of frequency leads to greater reduction of the dielectric permeability and this is more prominent in the samples of cotton and cotton/PET blend. The dc volume resistivity has been investigated in the function of relative humidity at room temperature and interpreted by the raw composition and the structural properties. On the basis of the obtained results, it was concluded that on the electrical properties of cotton/PET blend, cotton has greater impact i.e. the component with the higher dielectric permeability value and smaller dc volume resistivity value

Assessment of Electrical Behavior of Non-Woven Textile Materials

Non-woven textile materials have been increasingly used for a variety of applications in industry and daily life. This imposes a need for the investigation of electrical properties in different conditions of their usage. In the scope of this investigation, electrical conductivity and dielectric properties such as relative dielectric permeability and dielectric loss tangent of various polyester non-woven textile materials were determined. Experimental values of frequency were in the limits of 80 kHz to 2 MHz at relative environmental humidity of 30%. In addition, aimed at discovering the behaviour of investigated material from the aspect of electrical conductivity in various conditions of environmental humidity, the electrical conductance was measured both at 30% and 80% of relative environmental humidity in the electric periodic field at the frequency of 1 MHz All measurements were realised at the temperature of 30 degrees C. Obtained results showed that with the increase of frequency of electric periodic field electrical conductivity of tested samples increases, while the values of dielectric properties decrease. Furthermore, it was found that the increase of relative environmental humidity provokes the increase of electrical conductivity of tested non-woven sample

Investigation of the electrical behavior of some textile materials

Some electrophysical properties of textile samples having different forms and raw material compositions were studied. For determining the electric resistance, a measuring device, based on the measurement of direct current through textile samples, was developed. The dielectric loss tangents and relative dielectric permeabilities were measured for some of the-textile samples tested. The dielectric properties were measured using specially designed capacitance cells