Fabrication of Extrinsically Conductive Silicone Rubbers with High Elasticity and Analysis of Their Mechanical and Electrical Characteristics

Abstract

Conductive plastics are attracting more and more interest in electronics due to their light weight and inability to rust, which are common problems associated with metals. The field of conducting plastics is not new. Much work has been done to impart electrical conductivity to mechanically strong polymers such as polypropylene, polycarbonate and epoxies, etc. However there is a need to fabricate more flexible and elastic conductive polymers such as conducting silicone rubbers for use in various applications. In this work silicone rubbers reinforced with conductive fillers have been fabricated for use as sensors in textiles to detect the resistance change produced by stretching or relaxing. The variations of electrical resistance have been investigated by stretching and releasing the strands of conductive rubbers as a function of time. Two types of silicone rubbers—addition cured and condensation cured—were compounded with different electrically conductive fillers, among which carbon fibers have shown the best results. The carbon fibers improved the electrical conductance of the rubbers, even in very low weight percentages. The increasing concentration of fillers decreases the elasticity of the rubber. In order to keep the original properties of silicones, the filler concentration was kept as low as possible to produce a significantly detectable signal. The fabricated compounds were analyzed for their mechanical properties by stress strain curves. Such materials find their applications in electronics, antistatic applications, sports and the automotive industry where they can be used as deformation sensors.