Nonisothermal Thermal Decomposition Reaction Kinetics of Double-base Propellant Catalyzed with Lanthanum Citrate

Abstract

The decomposition reaction kinetics of the double-base (DB) rocket propellant composed of the mixed ester of triethyleneglycol dinitrate (TEGDN) and nitroglycerin (NG), and nitrocellulose (NC) with lanthanum citrate as a combustion catalyst was investigated by thermogravimetry and differential thermogravimetry (TG-DTG), and differential scanning calorimetry (DSC) under atmospheric pressure and flowing nitrogen gas conditions. The results showed that the thermal decomposition processes of DB propellant had two mass loss stages: volatilization and decomposition of the mixed ester in the first-stage and exothermic decomposition reaction in the second-stage. The exothermic decomposition reaction mechanism obeyed the third-order chemical reaction rule. The kinetic parameters of the reaction were: E a=231.14 kJ·mol –1, A=10 23.29 s –1. The kinetic equation can be expressed as: d α/d t=10 22.99(1– α) 3e –2.78×10 4/ T . The critical temperatures of the thermal explosion of the DB propellant obtained from the onset temperature ( T e) and the peak temperature ( T p) were: T be=463.62 K, T bp=477.88 K. The entropy of activation (Δ S ≠), enthalpy of activation (Δ H ≠), and free energy of activation (Δ G ≠) of the reaction were 219.75 J·mol –1·K –1, 239.23 kJ·mol –1, and 135.96 kJ·mol –1, respectively.