ABSTRACT
320Polymer composites with conductive properties have been of researchers’ interest due to the great opportunities they provide for a variety of applications. Usually, they are insulators, but with suitable fillers, their electrical conductivity can be varied within a wide range. There is a theoretical possibility to create polymer composite materials with semiconductor properties, comparable with those of inorganic semiconductors, by mixing the polymer matrix with suitable fillers. The difficulties are due to impurities and imperfections existing in the structure of the macromolecular network, which because of the transport of charged particles is uncontrollable.
We used SiC, B4C, and TiB2 as functional fillers in elastomer composites based on natural and acrylonitrile butadiene rubber. The dielectric (dielectric constant and dielectric loss angle tangent) properties of the obtained vulcani- zates and the changes in them caused by different factors (fillers concentrations, pressure, bending, temperature, etc.) have been determined.
The mechanism of charge transfer has been clarified via the parameters characterizing it (activation energy, mobility, content, and type of the charge carriers) as well as the impact that the composites structure has on their electrical and mechanical properties. The change in the electrical and tensile properties of the composites resulting from the thermal aging has been monitored.
The results from our investigations have shown that the composites could be included in electric circuits and transform nonelectric variables into electric. We have determined experimentally the ranges in which the composites studied can act as high frequency fillers, thermal sensors, sensors of pressure and great bending, shields in nuclear industry, materials with high coefficient of thermoconductivity, and so forth.
