The Catalytic Effect of Mn2O3 Nanoparticles on the Ignition Reaction of Pyrotechnic of Ammonium Nitrate(V)/Thiourea

The non-isothermal TG/DSC technique has been used to study the kinetic triplet and heat of ignition reaction of ammonium nitrate(V) (AN)/thiourea (TU) pyrotechnic in the presence of Mn2O3 catalyst nanoparticles under an argon atmosphere at different heating rates (5 K·min−1, 10 K·min−1, 15 K·min−1 and 20 K·min−1). The activation energies for the ignition reaction of AN/TU were calculated using the non-isothermal isoconversional Kissinger-Akahira-Sunose (KAS) and Friedman equations for different conversion fraction (α) values in the range 0.1-0.9. The pre-exponential factor and kinetic model were determined by means of the compensation effect and the selected model was confirmed by a nonlinear fitting method. The average activation energies in the absence and presence of 5 wt.% Mn2O3 nanoparticles were 110.1 kJ·mol−1 to 117.3 kJ·mol−1 for the reaction model A3 (g(α) = [−ln(1−α)]1/3), and 86.5 kJ·mol−1 to 101.8 kJ·mol−1 for the reaction model A4 (g(α) = [−ln(1−α)]1/4). The evolved heat (ΔH) of ignition reaction in the presence of Mn2O3 was about 4 times that in the absence of the nano-sized Mn2O3.