Conductive Poly(epichlorhydrin)–Polyaniline Dodecylbenzenesulfonate [PECH-PAni.DBSA] Rubber Blends Prepared in Solution

Abstract

Blends of poly(epichlorhydrin) elastomer [PECH] and polyaniline dodecylbenzenesulfonate [PAni.DBSA], with electrical conductivities up to 6.4×10−7 S cm−1, have been prepared by solution mixing and casting. The solubility parameters were calculated and the most suitable solvent (tetrahydrofuran) was selected for mutual solubility between PAni.DBSA and the compatible elastomer poly(epichlorhydrin) [PECH]. Fourier-transform infrared (FT-IR) spectra of PECH-PAni.DBSA blends contained features of the spectra of the pure materials, but with significant peak shifts due to changing intermolecular interactions between the polymers. Thermal decomposition steps of the conductive blends were investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The thermal stabilities of the blends were dependent on the ratio of PAni. DBSA to PECH. The electrical conductivities of blends with proportions of 1 to 50 wt% PAni.DBSA were measured by 2-probe and 4-probe techniques. The electrical conductivity increased with the proportion of PAni.DBSA, showing two percolation threshold stages, which were explained by a change in the conformation of the polymeric chains leading to an increase in the conductivity. The effects of composition on the glass transition in the blends were determined using thermomechanical analysis (TMA).