摘要
共晶炸药是目前含能材料研究领域的重点,然而由于主客体分子结合力的限制,绝大多数共晶炸药稳定性较差,在热刺激作用下容易发生结构相变或分解。红外光谱是研究这类共晶炸药相变行为的重要手段,尤其是二维相关红外光谱技术具有灵敏度高、解析能力强的优势,在共晶炸药结构演变研究方面具有独特的优势。本文采用原位红外光谱法和二维相关分析技术分别研究了TNB、TNT和TNB/TNT共晶炸药在热刺激作用下(25℃~150℃)的晶体相变行为。结果表明:二维相关光谱的移动窗口技术不仅能够精准确定炸药的相转变区间,还能够确定炸药分子基团周围化学环境的改变过程,相比较传统的DSC、XRD和Raman等技术具有显著的优势。通过对TNT-TNB共晶炸药的熔融过程中氢键结构的研究,发现共晶炸药中形成的弱的氢键作用是共晶炸药耐热稳定性的弱点,在热作用下首先断裂引发整个分子间氢键作用的变化,即弱氢键结构是共晶炸药熔融的起始点。
Co-crystal explosives have attracted a lot of interests in the field of energetic materials. However, most co-crystal explosives are instable and easy to occur phase transition or decomposition under thermo-stimulation. Infrared spectroscopy and two-dimensional correlation infrared spectroscopy(2DCOS) are important methods to investigate the phase transition of co-crystal explosives. In this study, the phase transitions under thermo-stimulation(25℃~150℃) of TNB, TNT, and TNB/TNT co-crystal were investigated by in-situ infrared spectrum and 2DCOS. The results indicate that the moving window technology of 2DCOS could not only determine the phase transition range of explosives, but also reveal the change in chemical surroundings of groups of explosive molecules, which showed remarkable advantages compared with DSC, XRD and Raman. According to the investigation on hydrogen bonds of TNB/TNT co-crystal in the process of melting, it was found that the weak hydrogen bonds forming in the co-crystal explosive resulted the instability of co-crystal explosive under thermo-stimulation. The hydrogen bonds were easy to be broken under thermo-stimulation, which induced the changes of hydrogen bonds of inter-molecules.
引文