We performed a kinetic study applying model fitting and the iso-conversional method to investigate the thermal decomposition behaviors of GAP ETPE/RDX-based solid propellant (ETPE propellant). The ETPE propellant consists of GAP ETPE and RDX was processed by an extrusion method. The surfaces of the ETPE propellant exhibited heterogeneous surface structure with noticeable RDX particles. The DSC results showed that the GAP ETPE played a role in lowering the thermal decomposition temperature of the ETPE propellant. The TGA results demonstrated that the decomposition process of the ETPE propellant progressed in one stage in the temperature range of 150-250 degrees C. From the kinetic analysis, with the GAP ETPE in the ETPE propellant, the activation energy was maintained up to alpha <0.2 at 170 kJ/mol, preventing evaporation of liquid RDX. (C) 2012 Elsevier B.V. All rights reserved.