Analysis of evolved gases during the thermal decomposition of ammonium diniramide under pressure

Ammonium dinitramide (ADN) is one of the most promising new solid oxidizers for rocket propellants, since its oxygen balance and energy content are relatively high, and it does not contain halogens. To gain a better understanding of the thermal decomposition mechanism of ADN, the thermal behavior and gaseous products from decomposition of ADN under pressurized condition (0.1-2.1 MPa) were investigated. The main reaction under all pressures was the decomposition of ADN to ammonium nitrate and nitrous oxide, although a new significant exothermic reaction was observed to occur beforehand. The relative amount of nitrogen dioxide decreased with increasing pressure. These results of this work indicate that condensed phase reactions involving nitrogen dioxide take place during the initial stage of the thermal decomposition of ADN. It was thought that the generation and decomposition of highly reactive materials to ammonium nitrate (AN) were promoted by nitrogen dioxide, and the reaction mechanism changed when the amount of AN in condensed phase increases.