The thermal behavior of the carbohydrazide complexes of certain metals (5) : Combustion reaction of the Zn and Mn complexes with oxidizing agents

Carbohydrazide (hereafter, CDH) metal complexes are expected to be a new gas generant for automobile air bags. After the previous report 4∼7) , the combustion reaction of the Zn and Mn complexes with various oxidizing agents (KClO 4 , KBrO 3 , KNO 3 and Sr(NO 3 ) 2 ) was investigated by thermal analysis and the measurement of the heat of combustion, the burning temperature and the burning rate. During the decomposition at a slow heating rate, such as in thermal analysis, the initial temperature of the reaction in the binary system with KBrO 3 was the lowest with the most vigorous reaction in both complexes. Furthermore, it was clear that the reactivity increased with the addition of CuO to the Zn complex/oxidizing agents system. In the Zn complex, the heat of combustion at a stoichiometric composition increased in the order of Sr(NO 3 ) 2 , KNO 3 , KClO 4 and KBrO 3 of the oxidizing agent. However, this tendency was inconsistent with that of the calculated value. The burning rate in the complex/KBrO 3 system was the highest of all systems and increased in the order of the above oxidizing agents with the same tendency as the heat of combustion. The burning rate in the Zn complex/ oxidizing agent/CuO system seems to be governed by the heat of combustion and the reaction rate. On the other hand, in the Mn complex, both the heat of combustion and the burning rate increased in the order of Sr(NO 3 ) 2 , KBrO 3 and KClO 4 , agreeing with the tendency of the calculated value. The burning rate in the Mn complex/oxidizing agent system seemed to be governed by the heat of combustion. However, in the mixture system with KClO 4 , the pressure exponent was larger, and no combustion occurred at atmospheric pressure.