A fundamental study on the thermal decomposition and combustion behaviors of guanidine nitrate and basic copper nitrate mixture

Energetic materials such as a mixture of guanidine nitrate (GN)/basic copper nitrate (BCN) are used as gas generators in automotive airbag systems. However, at the time of the airbag inflation, the gas generators release toxic combustion gases such as CO, NH3, and NOx. In this study, we investigated the combustion and thermal decomposition behaviors of GN/BCN mixture, focusing primarily on their exhaust gas composition. As a result, when the exhaust gas of the combustion under constant pressure in an inert gas stream was analyzed using a detection tube, the amount of NOx (mainly NO) yielded greater decrease with increasing atmospheric pressure as compared to the amounts of CO and NH3. Thus, provided GN/BCN is ignited in a closed container, a large amount of NOx is presumed to have been released during the initial stage of combustion, which yielded comparatively low pressure. Results of the thermogravimetry-differential scanning calorimetry-Fourier transform infrared spectroscopy (TG/DSC/FTIR) indicated that the GN/BCN mixture caused endothermic decomposition at 170 A degrees C and exothermic decomposition at 208 A degrees C, which was accompanied by 66% mass loss. The decomposition gases, CO2, N2O, and H2O, were detected via FTIR spectrum. Because N2O was not detected in the combustion gas, it was suggested that the detected N2O was generated at a low temperature and decomposed in high-temperature combustion.