原位漫反射红外光谱研究升温速率对HMX炸药热分解过程的影响

原位红外光谱法是一种新兴的动态研究方法.该方法具有原位实时监控和红外光谱精确分析物质化学结构的优点,能够实时跟踪材料在不同温度下的化学变化,测定材料的微观结构与温度的关系.采用原位漫反射红外光谱研究了炸药1,3,5,7-四硝基-1,3,5,7-四氮杂环辛烷(HMX)分别在每min 5,10,20和40℃四种不同升温速率下的热分解行为.研究结果表明:在5℃·min-1升温速率下,断裂的HMX环发生分子内结合,在10,20和40℃·min-1升温速率下,断裂的HMX发生分子间成环,形成稳定的八元环结构.随着温度的升高,C-N键的断裂数率远高于N-N键的断裂速率.随着升温速率的增加,C-N键的起始分解温度增加,表明增加升温速率会引起HMX分解的滞后.检测到HMX的分解所释放出CO2,N2O,CO,NO,HCHO,HONO,NO2和HCN共八种气体,升温速率的变化未改变HMX的分解机理.

Study on Effect of Heating Rate on Thermal Decomposition of HMX Energetic Materials by In-Situ Diffuse Reflection FTIR Spectrum

In-situ FTIR spectroscopy is a rising and dynamic technique. This technique combines the advantages of investigation in-situ and accurate structure analysis by FTIR spectroscopy, and can detect real time chemical change in materials at different temperatures and obtain the relationship between micromechanism of materials and temperature. In the present paper, thermal decomposition of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) heated with a rate of 5, 10, 20 and 40 degrees C x min(-1), respectively, was investigated by in-situ diffuse reflection FTIR spectroscopy. The results demonstrate that intramolecular cyclization occurs in breakage of HMX with a heating rate of 5 degrees C x min(-1), while intermolecular cyclization appears with a heating rate of 10, 20 and 40 degrees C x min(-1). With increasing temperature, the rupture rate of C-N bond is faster than that of N-N bond, which verifies that the cleavage of C-N bond is the dominant rupture form. With increasing heating rate, the decomposition beginning temperature of C-N bond increases. Eight kinds of gaseous products such as CO2, N2O, CO, NO, HCHO, HONO, NO2 and HCN were determined. The decomposition mechanism of HMX was not affected with changing heating rate.