THE EFFECT OF SILICON CARBIDE CERAMIC ON THE ELECTRICAL AND MECHANICAL PROPERTIES OF CONDUCTIVE BUTYL RUBBER COMPOSITES

Abstract

The present work is mainly concerned with the effect of the addition of the silicon carbide ceramic with different concenterations on the mechanical and the electrical properties of butyl rubber composites.

In the present work, a trail has been made to follow up and understand the conduction mechanism of SiC with different concentrations (0,2.5,5,7.5 and I 0 phr) added to rubber vulcanizes.

The unvulcanized samples were cured under a heater press at 175°C and 200 KN I m2 .The conductivities of these samples were measured during vulcanization as a function of time .For all samples, the electrical conductivities show an increase and reach an optimum value crm after a characteristic time for each sample .The constancy of conductivity was followed up to 3 hrs. This was taken as an indication of completeness of vulcanization process.

The current - voltage characteristics of vulcanized samples were studied at room temperature. These characteristic shows an ohmic behaviour up to certain limits of applied ,•oltage (V*), after which the sample may be heated up by Joule effect.

The temperature dependence of the electrical conductivity was

studied. The results show an increasing in the electrical conductivity with temperature. This increase in the electrical conductivity with increasing temperature may be attributed to the thermal activation of host temperature and to the thermal expansion of the hopping paths between the conducting silicon carbide particles or aggregates.