<p>The rubber components are often exposed to high temperatures and harsh environmental conditions which in turn degrade their performance and service life. To get insight into mechanism, structure and characteristics which can be affected by thermally induced changes in the composites thermogravimetric analysis are carried out. The study systematically investigates the thermally induced decomposition kinetics of novel ternary elastomeric composites comprising nitrile-butadiene rubber (NBR), chloroprene rubber (CR), and epoxidized natural rubber (ENR) which ensure compatibility of mixing via having almost equal solubility parameter values. Composites were formulated using a simplex centroid mixture design of DoE, and which can be cured either by sulfur or peroxide vulcanization process. Based on thermogravimetric analysis (TGA), the thermal degradation kinetics, with five model-free iso-conversional methods, are applied to determine kinetic parameters such as the activation energies (<i>E</i>a), pre- exponential factors (A) and the corresponding thermodynamic parameters enthalpy (<i>ΔH</i>), entropy (<i>ΔS</i>) and Gibbs free energy (<i>ΔG</i>) of the prepared composites. Supporting analyses, including FTIR spectroscopy and SEM morphology, were conducted to correlate possible chemical and structural changes with kinetic responses. The results highlight the influence of curing system and elastomeric composition on thermal stability and multistage degradation profiles, and further provide mechanistic insight into degradation pathways.</p> Graphical abstract <p></p>