Influence of temperature and fiber structure on the dielectric properties of polypropylene fibrous structures

摘要

In this work, dielectric spectroscopy was conducted on five commercial woven polypropylene-based fabrics. Measurements of dielectric loss tangent, the effective relative dielectric permeability and ac electrical conductivity were performed over a wide range of temperature and frequency. The results in temperature range from 250 K to 355 K showed that the samples with lower value of volume fraction whose yarn is made from a short fiber have a lower value of the above mentioned dielectric parameters than the samples with bigger value of volume fraction and filament yarn along the weft and the warp lines. Based on the results gained from the measurements in the vacuum and ambient conditions, it can be concluded that the samples with a lower value of volume fraction, whose yarn is made from a short fiber, showed stability of dielectric properties in the measurement interval.