Ammonium nitrate (AN) has been attracting attention as an oxidizer of gas generating mixtures. However, the gas generating mixtures that contain AN have the disadvantages that they are difficult to ignite, and that the burning rate is generally slow. In this study, aminoguanidinium 5,5'-azobis-1H-tetrazolate (AGAT), a tetrazole that could cause exothermic decomposition was used as a fuel, mixed with AN. To begin with, the initial decomposition of AGAT was examined by means of TG-DTA-MS. It was found that AGAT melted at 482 K, followed immediately by a dramatic decomposition, leading to 50 % weight loss. The decomposition of AGAT started from the cleavage of the heterocyclic ring which produced nitrogen and cyanamide with generation of heat. The burning rate of AGAT and AN mixture was also examined. Copper(II) oxide CuO or manganese dioxide MnO2 that has been widely known as the decomposition catalyst of AN was added to the mixture to enhance the mass burning rate. The addition of CuO to the mixture enhanced the mass burning rate and decreased the pressure exponent of Vieille's equation, but the addition of MnO2 did not enhance the mass burning rate. By means of thermocouples, the temperature profiles of the burning mixtures were also obtained and it was suggested that CuO may activate the reaction in the condensed phase reaction zone.
硝酸アンモニウムはガス発生剤の酸化剤として注目されてきた。しかし、硝酸アンモニウムを含むガス 発生剤は、着火し難く、燃速が小さいという欠点がある。本研究では、発熱分解するテトラゾールである aminoguanidinium 5,5'-azobis-1H-tetrazolate (AGAT) を燃料として使用し、硝酸アンモニウムと混合した。は じめに、AGAT の第1分解をTG-DTA-MS で調べた。AGAT は482 K で融解した直後に、重量減少50 ％に相等 する分解をすることが分かった。AGAT の分解は複素環の開裂で始まり、発熱を伴って窒素とシアナミドを生 成した。AGAT とAN の混合物の燃焼速度も調べた。硝酸アンモニウムの分解触媒として知られている酸化銅 (II)や酸化マンガン(IV)が質量燃速を増加させるために添加された。酸化銅(II)を添加すると質量燃速が増加し、 Vieille の式における圧力指数が減少したが、酸化マンガン(IV) を添加しても質量燃速は増加しなかった。熱電 対により燃焼混合物の温度履歴も得られ、酸化銅(II) は凝縮相反応層において反応を促進すると考えられる。
Ammonium nitrate, Aminoguanidinium 5,5'-azobis-1H-tetrazolate, Copper (II) oxide, Temperature profile, Condensed phase.