Pre-formulation Compatibility Studies of 5-Amino-1H-tetrazole Nitrate with Several Typical Materials by Thermal and Non-thermal Techniques

Wanxiao Guo, Zhiwei Han, Qiuhan Lin, Boliang Wang
2018 Central European Journal of Energetic Materials  
The aim of the present study was to assess the physicochemical compatibility of a promising energetic salt, 5-amino-1H-tetrazole nitrate (5-ATN), with some typical materials. Thermal techniques (differential scanning calorimetry (DSC) and vacuum stability test (VST)) and non-thermal techniques (X-ray diffractometry (XRD) and Fourier Transform Infrared Spectroscopy (FTIR)) were applied. Five energetic materials (TNT, RDX, HMX, CL-20 and AP) and three common additives (Al, DOS and F2604-2) were
more » ... and F2604-2) were tested to evaluate their compatibility with 5-ATN. Based on the DSC results, except for AP that was only partially compatible with 5-ATN, all of the selected materials exhibited good compatible with 5-ATN. The VST test further confirmed the compatibility of the 5-ATN/AP mixtures. Combined with the thermal methods, the FTIR results agreed with the DSC findings. The XRD results showed some differences. stabilities [2] [3] [4] [5] . Among these new molecules, tetrazole-based energetic species have drawn particular attention due to the high heat of formation (237 kJ/mol) for the five-membered nitrogen-rich ring of tetrazole (CH 2 N 4 ) [6] [7] [8] [9] . Previous studies of these compounds have focused on the synthesis of novel derivatives, some of which have high detonation properties and superior stabilities, or on the development of new synthetic pathways [10] [11] [12] [13] . 5-Amino-1H-tetrazole hydronitrate (5-ATN), a typical tetrazole-based energetic salt, has potential applications in propellants and gun powders due to its excellent properties: measured density 1.847 g·cm −3 ; nitrogen content 56.76%; oxygen balance −18%, molar heat of formation 87 kJ·mol −1 ; detonation velocity 8900 m·s −1 ; friction sensitivity >324N [6, 13] . Moreover, the synthetic process for 5-ATN is simple and easy to industrialize. The preparation, crystal structure, detonation properties and thermal behaviour of 5-ATN have been intensively studied [9, [14] [15] [16] . However, to our knowledge, few studies have concentrated on basic research for its applications, such as compatibility. It is well known that energetic materials are rarely used separately. Interactions arising from the incompatibility between the energetic material and the contacted components may further accelerate the rate of ageing, alter the shelf life and impair the chemical nature of the energetic material. Consequently, unexpected explosions due to decomposition reactions could result [17] . Therefore, the compatibility of new explosives is the first issue that should be investigated before formulation studies. Thermal methods, such as DSC and VST, have been outlined by the NATO Standardization Agreement STANAG 4147 for compatibility assessment. DSC has been proposed to be a rapid and efficient method to initially assess the compatibility of mixtures containing the active component and various contacted ingredients [18, 19] . Despite the stated advantages of the DSC method, one of its main drawbacks is the small amount of sample required (milligram scale). Interpretations deduced from DSC may not be suitable for larger samples [20] . VST is used routinely for compatibility assessment [21, 22] . The sample quantity (gram scale) used in a VST test is much more representative. However, the application of VST is limited partly because it is time consuming. Consequently, it is recommended that DSC and VST should be combined with each other for exploring compatibility issues. However, information from thermal studies should be interpreted carefully in order to avoid erroneous judgements and conclusions [23] . Therefore, some non-thermal techniques have been frequently used to expand on the thermal behaviour that is not observed at room temperature. Besides the thermal methods, XRD and FTIR have contributed significantly in the search for possible interactions in pharmaceutical chemicals [24] [25] [26] . To our knowledge, the
doi:10.22211/cejem/81081 fatcat:odcgs27vufcyxbf3twt2h2wuzq