Electrically conductive elastomer composites containing polyaniline

The electrical conductivity and mechanical properties of several elastomer-based composites containing polyaniline-dodecylbenzene sulphonic acid (PANI-DBSA) complex: have been studied. An inhomogeneity of these materials (heterogeneous microdispersion of the particles of the conductive constituents - carbon black and PANI) was found. It was shown that structural changes took place within the blends during storage, causing perceptible changes in the state of the conductive pathways. This nonequilibrium nature and, as a consequence, the unstable behaviour of the composites was revealed using both average conductivity and average conductivity deviation methods. A substantial decrease in the glass transition temperature (Delta Tg ca. 5-15 C) of the insulating matrix polymer (styrene-butadiene rubber, nitrile-butadiene rubber or ethylene-propylene-diene terpolymer) in the composites was also found. The lowering of Tg has been attributed to the presence of DBSA (free and as counter-ions of the main PANI chains), which plasticized the polymer composites. From an industrial point of view, the preparation of composites containing the PANI-DBSA complex is of great importance since the processability of the mixtures is facilitated.