四种液态含能材料热感度的探索性研究

【作者】 陆燕；

【导师】 陈网桦；

【作者基本信息】 南京理工大学 ， 安全技术及工程， 2008， 硕士

【摘要】 热感度是物质在热作用下发生化学反应难易程度的度量,通常可以通过起始分解温度（考虑物质初始分解时的情形）、5秒爆发点（考虑物质快速分解时的情形）、真空安定性等方法表示。液体含能材料由于其挥发性,传统的方法很难获得类似5秒爆发点、真空安定性方面的参数。本论文主要通过加速度量热仪（ARC）和差示扫描量热仪（DSC）研究了液态含能材料硝基甲烷NM、硝酸正丙酯NPN、硝酸异丙酯IPN和硝酸异辛酯EHN的热分解,并在热分解的基础上研究了不同阶段的热感度。首先,采用DSC和ARC的实验手段,对以上四种物质进行了测试,分析了相关的热力学、动力学参数和实验条件对结果的影响,进行了热危险性的分析,得到了这四种物质在初始分解时的热感度从高到低为:EHN＞NPN＞IPN＞NM。然后,根据反应延滞期与温度的关系,以ARC实验结果为依据,计算获得了上述四种物质在最大反应速度到达时间TMR为0.5min、1min、5min时的温度,并以TMR为0.5min时的温度作为快速反应阶段热感度的判据,这四种物质的热感度从高到低排列为:NPN＞EHN≈IPN＞NM;同时在获得TMR与温度关系曲线的基础上,引入时间常数τ,估算了这四种物质在三种不同容器中的自加速分解温度SADT;另外还探讨了量子化学中的键离解能BDE和以上四种物质起始分解温度的关系,得到绝热下起始分解温度与BDE的关系式为:T_ARC=1.311BDE-70。最后,研究了酸对EHN热分解的影响,结果表明:H₂SO₄能使其起始分解温度下降,热感度提高;HNO₃能使其反应速率加快,热感度提高;硝硫混酸（质量比为1:2）则呈现出与H₂SO₄类似的影响作用,能使其起始分解温度降低,热感度提高,但影响作用稍弱。更多还原

【Abstract】 Thermal sensitivity is a measurement on how easily chemical reaction can happcn, which can be expressed by the parameters of onset temperature,5 s delayed explosion temperature and VST.Generally,liquid energetic materials are too volatile to get the parameters above.So,the thermal sensitivity and decomposition of four liquid explosives, nitromethane（NM）,n-propyl nitrate（NPN）,isopropyl nitrate（IPN）and 2-ethylhexyl nitrate（EHN）are studied by Accelerating Rate Calorimeter（ARC）and Differential Scanning Calorimeter（DSC）in this paper.First of all,the decompositions of the tour liquid explosives are studied by DSC and ARC.Kinetic and thermodynamics parameters are calculated and analyzed.The influence of the experimental conditions and their thermal hazards are both compared and considered.According to the decomposition onset temperatures of both DSC(T_dse) and ARC（T_arc）),it can be founded that,at the start of thermal decomposition,EHN is the most sensitive,NPN is less sensitive than EHN and more sensitive than IPN,and NM is the least sensitive.Secondly,on the basis of the ARC data,0.5min,1min and 5min are chosen as the time to maximum rate（TMR）to calculate their corresponding temperatures.The temperature where TMR equals to 0.5min is selected as a criterion for thermal sensitivity evaluation when it goes to thermal explosion.By the criterion,it can be founded that NPN is the most sensitive,EHN is less sensitive than NPN,but close to IPN,NM is the least sensitive.Self-accelerating decomposition temperature（SADT）of the four liquids in three different containers are estimated according to the time constantτand the curve of TMR vs Temperature.Bond Dissociation Energy（BDE）calculated by the quantum chemical calculations are used to obtain T_ARC,with the expression as:T_ARC= 1.311BDE—70.At last,the decomposition of EHN with acids are studied,and the results is shown as follows:sulfuric acid can decrease the onset temperature of decomposition and increase thermal sensitive;Nitric acid can accelerate the decomposition of EHN,enhance thermal sensitive;Mixed acid(m_H2SO4:m_HNO3= 2:1)is of the influence similar to sulfuric acid except the influence is weaker.更多还原