Thermally stimulated depolarization currents (TSDC) characteristic of styrene butadiene rubber (SBR)-graphite composites.

Thermally stimulated depolarization current (TSDC) analysis is a powerful technique for analyzing dielectric relaxation in polymer-based composites. In this study, the TSDC behavior of styrene-butadiene rubber (SBR) composites loaded with 40, 60, and 100 phr of graphite was investigated. The composites were prepared using open mill mixing followed by hot press molding. TSDC measurements were performed at 383 K under various polarizing fields. The spectra exhibited multiple relaxation peaks attributed to dipolar and space charge polarization mechanisms. The data were analyzed using the Bucci and Garlick-Gibson methods, and the molecular parameters such as activation energy, charge released, and relaxation time were examined. The results reveal that both graphite concentration and the applied polarizing field significantly influence the relaxation behavior. These effects are associated with variations in dipole alignment, charge trapping dynamics, and electrode polarization. The results provide insights into dielectric relaxation processes in conductive polymer composites and may inform future research on potential applications in sensors and electromagnetic interference (EMI) shielding.