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The contradiction between flammability and packing density is the technical bottleneck for combustible smoke agent. Herein, polyurethane (PU) foams with flammability and resilience were prepared with polyol and isocyanate as raw materials by chemical foaming method, then compounded with metal powders, polytetrafluoroethylene (PTFE), phthalic annychide (PA), etc. in a certain proportion and pressed into pyrotechnic grain to obtain eco-friendly combustion aerosols with compact density of about 1.15 g/cm3. The resulting combustion smoke agent combined the advantages of PU foam and pyrotechnic with easy ignition, large smoke production, long duration and low environmental pollution. The transmittance of aerosols for 532 nm and 1064 nm lasers was close to 0, and the EMI SE reached up to 65 dB and 35 dB in GPS band and X band, respectively. In addition, the resulting pyrotechnic grains exhibited good mechanical strength and elasticity for sample 1:25, with a compressive strength of 22 MPa and an elastic modulus of 195 MPa. The resulting combustion smoke agent is expected to play a potential role in the field of electromagnetic damage and protection. [ABSTRACT FROM AUTHOR]

In the present study, thermal hazards of TNT and DNAN used as the molten binder in TKX-50-based meltcast explosives were comparatively studied through accelerating rate calorimeter (ARC) and Cook-off experiments. Two kinds of ARC operation modes were performed to investigate the thermal safety performance under adiabatic conditions (HWS mode) and constant heating (CHR mode). The obtained results demonstrated that at both heating modes, DNAN/TKX-50 outperformed TNT/TKX-50 from the thermal safety point of view. However, the sensitivity to heat of the samples was reverse because of the different heating modes. In addition, the results of thermal hazard assessment obtained from the cookoff experiment complied with ARC analysis which indicated the molten binder TNT replaced by DNAN would reduce the hazard of the TKX-50 melt cast explosive. Furthermore, the results of cook-off experiments also showed that DNAN/TKX-50 outperformed TNT/TKX-50 from the aspect of thermal stability, which was consistent with the result of CHR mode because of the similar heating process. [ABSTRACT FROM AUTHOR]

3-nitro-1,2,4-triazol-5-one (NTO) is the main component of insensitive munitions (IM) formulation because of its outstanding insensitive properties. In this paper, a series of NTO/HMX-based composite explosives were prepared and characterized. The study focuses on the effect of NTO on the performance of the formulations, especially the safety performance. The results revealed that the mechanical sensitivity of formulations was associated with NTO content, as well as the thermal conductivity, specific heat capacity and Arrhenius parameters. Then, the high amount of NTO using in formulation was proved to be helpful for NTO/HMX-based formulation to exhibit good thermal safety. Besides, by accelerating rate calorimeter (ARC) and a modified cook-off equipment, the pressure and pressure rise rate were proved as the important indicator for judging the thermal safety performance in confined spaces. Finally, the numerical simulation was used as a credible method for predicting the respond temperature of cook-off experiment. [ABSTRACT FROM AUTHOR]

Alkaline Earth metal (Mg) energetic complex with 5,5′‐dinitramino‐3,3′‐bi[1,2,4‐triazolate] dihydrate (DNABT) has been synthesized and structurally characterized by FTIR spectroscopy, elemental analysis, and single X‐ray diffraction. The thermal decomposition processes of the complex and DNABT were studied by means of the TDA‐TG technologies. Sensitivity tests reveal that the complex is more insensitive to mechanical stimuli than DNABT. Combustion behavior shows that 1 has good color performances. [ABSTRACT FROM AUTHOR]

Four transition metal energetic complexes with 5,5′-bistetrazole-1,1′-diolatedehydrate (BTO) have been synthesized and structurally characterized by FT-IR spectroscopy, elemental analysis, and single X-ray diffraction. The thermal decomposition processes of the complexes and BTO were studied by means of the TG-TDA technologies. The compatibility of the four complexes with RDX, HMX, NC, and Al powder was also investigated. Sensitivity tests reveal that the complexes are more insensitive to mechanical stimuli than RDX. [ABSTRACT FROM AUTHOR]

5,5′-Bistetrazole-1,1′-diolate-based energetic salts from alkaline (Li+, K+, and Na+) and alkaline earth metal salts (Mg2+, Ca2+, and Ba2+) were synthesized in a simple, straightforward manner and were characterized by IR and NMR spectroscopy, and elemental analysis. Single-crystal X-ray diffraction of 4 salts (Li+, Na+, K+, and Mg2+) is given. The X-ray structures show that in the title compounds, the metal atoms are bonded to the nitrogen and oxygen in the bistetrazole ring to form the sandwich structure. In addition, thermal stabilities of all title compounds were determined with differential thermal analysis-thermal gravity analysis. All these new materials exhibit excellent thermal stabilities, high density, and excellent insensitivity to impact ( h50 > 60 cm) . Especially, the potassium salt is of interest as potential 'green heat-resistance explosive' with high density and high thermal stability as well as low sensitivity. [ABSTRACT FROM AUTHOR]

Specific heat capacity of AAOF was studied from −15 to 70 °C. The equation describing the relationship can be written as Cp = 0.8483 + 0.00384 × T, −15.0 °C ≤ T ≤ 70 °C. Thermogravimetric thermal analysis and accelerating rate calorimetry (ARC) were performed to understand thermal characteristics and kinetics of energetic 3-amino-4-amidoximinofurazan (AAOF). Thermal decomposition occurred at 217.08, 228.91, 239.24, 255.78 °C at different heating rates (1.0, 2.0, 4.0 and 8.0 °C min). ARC tests showed that the self-decomposition reaction of AAOF started at 197.4 °C and lasted for 86 min with the maximum temperature rise rate (152.33 °C min) and the pressure rise rate (10,881 kPa min). By applying ARC test data in 16 kinetic models in formula, the most possible mechanism functions, apparent activation energy ( E ) and pre-exponential factor ( A) for the decomposition of AAOF were $$ (1 - \alpha )^{2} $$ , 226.19 kJ mol and 4.59 × 10 s. In addition, the SADT of AAOF in 25 kg package is 205.37 °C based on ARC data. [ABSTRACT FROM AUTHOR]

2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (HNIW) was bonded by fluorine rubber and then desensitized by paraffin wax (PW), stearic acid (SA), and a PW/SA composite system using an aqueous suspension method. The coating and desensitization effects of the composite systems on HNIW and the influence of the addition of SA on the mechanical properties of the coated HNIW samples were studied. In addition, the PW/SA composite solution was simulated using a molecular dynamics method, and the relationship between the desensitization effect on HNIW and the properties of the composite solution was investigated. The results showed that the PW/SA composite system, of which the desensitization effect on HNIW was between those of the two desensitizers, could effectively coat HNIW and that the composite solution had the most stable and well-distributed state when using benzene as solvent with the mass ratio of PW/SA equal to 7/3 or 3/7, thus resulting in the best desensitization effect on HNIW. Moreover, the addition of stearic acid was successful in enhancing the mechanical properties of the coated HNIW samples. [ABSTRACT FROM PUBLISHER]