Thermal decomposition kinetics of ammonium dinitramide–guanylurea dinitramide mixture analyzed by isoconversional methods

Abstract

The thermal decomposition kinetics of a mixture of high-energy oxidizers ammonium dinitramide (ADN) and guanylurea dinitramide (GUDN) have been studied by nonisothermal differential scanning calorimetry (DSC). Friedman's and Vyazovkin's advanced isoconversional (AIC-V) methods were used to investigate the dependence of activation energy ( E a) on conversion ( α). A strong dependence of E a on α was observed, indicating a complex decomposition process. E a is ∼165–175 kJ mol −1 at the start of the reaction, then reaches a maximum of ∼196–199 kJ mol −1 at α = ∼0.4, followed by a strong decrease to ∼135 kJ mol −1 near the end. E a has also been determined for the mixture and the individual components using Kissinger's method. Our results suggest that the decomposition of ADN greatly influences the observed E a dependence on α. This is further supported by Fourier transform infrared (FTIR) results and the enthalpy values of exothermic decomposition.