A monitoring of the kinetics thermally degradation selected rubber by electrical methods

The work presents the possibilities of diagnostics of irreversible chemical reaction - thermal degradation in case of industry prepared rubber mixture based on styrene - butadiene (SBR) using measurements of selected physical parameters. Our attention was focused on the measurement of electrical parameters (electrical conductivity). Procedure of the measurement of electrical properties was applied at the constant temperatures from the range 150 °C to 200 °C. The determination of electrical properties by means of the measurements of time dependencies of alternate conductivity (σAC=σ(t)), were performed in frequency range 20Hz - 100kHz. It is possible describe significant constants of the kinetics of degradation reaction (reaction rate coefficient) by the solution of differential equations and by mathematical approximation. The constants are exponentially dependent on the temperature of thermal degradation. In addition the approximation allows describe the thermal degradation in the temperature range outside of the monitoring interval. © 2019 Author(s).Slovak Science Foundation [VEGA 1/0235/18]; Research & Development Operational Programme - ERDF [ITMS: 26220120048