甲基紫试验中改性双基推进剂的热分解机制研究

目的 研究甲基紫试验中含Al改性双基推进剂以及含RDX改性双基推进剂2种典型改性双基推进剂的热分解机理。方法 将这2种典型改性双基推进剂与普通双基推进剂进行对比试验，采用TG-DSC-FTIR-MS联用技术，通过对分解温度、放热量、分解产物等特征参数进行分析，明确3种推进剂的非等温热分解行为。采用微热量热法，在与甲基紫试验相同温度下对3种推进剂进行等温热分解行为研究。结果 含Al改性双基推进剂在程序升温条件下的热质量损失和热分解行为与普通双基推进剂的基本一致。含RDX改性双基推进剂中的NG较其他2种推进剂更易挥发，相应分解反应初期NG分解释放的NO2较少，且在整个热分解反应历程中分2个阶段，含硝酸酯基团的NC/NG体系先分解，再引起硝铵炸药RDX的热分解。在等温条件下，3种推进剂在40 min对应的反应深度均不超过0.4%，5 h对应的反应深度均不超过3%。但在分解反应初期，含Al改性双基推进剂分解反应的速率更快。结论 对比不同推进剂甲基紫安定性试验结果，并不是甲基紫试纸完全变色时间越长的热安定越好，说明甲基紫安定性试验方法存在一定的局限性。采用分解反应深度作为量气和量热方法转换的纽带，有望采用微热量热作为甲基紫试验的替代技术实现安定性的定量评价。

Therm Decomposition Mechanism of Modified Double-base Propellant in Methyl-violet Test

The work aims to study the thermal decomposition mechanism of two typical modified double-base propellants, respectively containing Al and RDX in the methyl-violet test. A comparative experiment was conducted to double-base propellants with TG-DSC-FTIR-MS combined technology. By analyzing characteristic parameters such as decomposition temperature, heat release, and decomposition products, the non isothermal decomposition behavior of the three propellants was identified. The isothermal decomposition behavior of three propellants was studied by microcalorimetry at the same temperature as the methyl-violet test. The thermal weight loss and thermal decomposition behavior of Al modified double-base propellants under programmed heating conditions were basically consistent with those of double-base propellants. NG in RDX modified double-base propellants was more volatile than that in the other two propellants, and the corresponding decomposition reaction released less NO2 during the initial stage of NG decomposition. The entire thermal decomposition reaction process was divided into two stages, where the NC/NG system containing nitrate groups firstly decomposed and then caused the thermal decomposition of ammonium nitrate explosive RDX. Under isothermal conditions, the reaction depth of the three propellants at 40 min did not exceed 0.4%, and the reaction depth at 5 h did not exceed 3% of the reaction depth, but the decomposition reaction rate of Al modified double-base propellants was faster in the early stage of the decomposition reaction. Through comparison between the stability test results of different propellants, it is found that the longer complete color change time of the methyl violet test paper does not mean the better thermal stability, indicating that the methyl-violet stability test method has certain limitations. The use of decomposition reaction depth as the link between measuring gas and calorimetry methods is expected to achieve quantitative evaluation of stability with microcalorimetry as an alternative technique for methyl-violet test.