Electrically Conductive Silicone/Organic Polymer Composites

Electrically conductive silicone elastomers carbon composites are the current state-of-art for electrically conductive elastomers. The combination of inorganic and organic polymers leads to a highly electrically conductive composite which has improved thermal stability. In this work, composites were formed, from two different classes of room temperature vulcanizing inorganic silicone polymers (vinyl & hydroxyl methyl silicone elastomers) (RTV-SI), which undergo curing by addition and condensation curing respectively, by a mixing and casting method. The organic polymer, which is the camphor sulfonic acid doped polyaniline (Pani.CSA) was synthesized by oxidative polymerization of aniline. By selecting RTV-SI system, the possibility of oxidative interaction of Pani.CSA that takes place at high temperature with curatives (peroxides) is ruled out. This helps to retain the conductivity of Pani.CSA and avoids the curing retardation of rubber. The concentration of Pani.CSA in the composites was varied from 20–40 phr. The electrical, thermal, morphological and short term stress - strain properties of the composites were studied after curing. A sharp decrease was observed in the resistance from ∼10ˆ15 Ω for blank silicone rubber to 27–31.5 KΩ for the filled composites with good thermal stability. The homogeneity of the composites was verified from SEM. The hardness of the composites was observed to increase by 3–5 on the Shore A scale. Tensile strength, tear strength and rebound resilience all decreased slightly.