Study of the thermal stability of Nitrile rubber-coconut flour compounds

The aim of the present work was to study the kinetics of the thermal degradation and the degradation mechanisms of neat nitrile rubber (NBR)-coconut flour (treated and non-treated) compounds. Thermogravimetric analysis was followed under N2 atmosphere from 25 °C to 700 °C, with the purpose of evaluating the thermal stability of the blends, and determining the kinetic parameters according to the E2 Function and Invariant Kinetic Parameters (IKP) methods. The thermal stability of NBR was increased significantly when coconut flour was added, increasing the Einv from 89 kJ/mol to 277 kJ/mol. When coconut flour was treated with zirconate, the positive effect on the thermal stability was even higher (Einv 298 kJ/mol). In addition, no significant changes were obtained in the maximum temperature of decomposition when the filler was present. With regard to the degradation of NBR, it can be concluded that it takes place according to the following degradation mechanisms: nucleation and nuclei growth, interphase reaction, reaction order and power law. The NBR-coconut flour compounds do present these degradation mechanisms plus the diffusion mechanism.