Ionic liquids (ILs) can function as “green” solvents owing to their stability and low vapor pressure. These features help prevent the ignition of a reaction and therefore ensures its safety. In this study, the application of ILs in the synthesis of energetic materials was examined; this was accomplished using nitration reactions in an IL, i.e. 1-butyl-3- methylimidazolium trifluoromethanesulfonate [BMIM][OTf] to determine its effect on runaway reactions. In this study, the nitration process generated o-, m-, and p-nitrotoluene (NT) with by-products; the major by-product was benzoic acid (BA), and the ratio of the weight of the NTs to the BA was ～90%. Furthermore, the presence of oxygen facilitated the production of BA. The amount decreased to 0.45% under nitrogen atmosphere in a closed instrument. This investigation showed that oxygen was one of the key factors to the generation of BA, which was considered a characteristic feature of the nitration in [BMIM][OTf]. The presence of BA reduces the temperature required to initiate the exothermic reaction of the NTs. However, neither the benzoic-acid-induced temperature decrease nor the heat-of-reaction-induced adiabatic temperature increase facilitated the attainment of a temperature that triggered the decomposition of NTs or IL.

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Scaled model tests are the most extensively used methods for evaluating blasting performance. This study conducted the scaled model test of bench blasting to evaluate the stemming effect of the blast hole. Blasting experiments were conducted using emulsion explosives, wherein general stemming (sand) and shear-thickening fluid (STF)-based stemming materials were used in the blast hole. The blasting experiment results revealed that the STF-based stemming materials were superior to the general stemming material. In addition, the dynamic strain measurement results on the concrete surfaces of the high-speed three-dimensional digital image correlation system signified that the displacement and surface strain on the test models were the highest in the experimental case of STF-based stemming materials.

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Some ammonium perchlorate composite propellants have an intermediate self-quenching pressure range around several MPa. When the propellant burns in a motor with an appropriate throat area, the motor changes its chamber pressure in dual combustion modes. The objective of this study is to make cyclic combustion-mode transitions and to achieve the thrust magnitude control of solid rocket motor. The transitions from the low mode to the high mode were attained by nitrogen gas injection, and those from the high mode to the low mode were done by a brief gas release with appropriate nitrogen gas injection. Without the gas injection, the transition from high mode to low mode was not accomplished and the combustion was interrupted. The timing to shut down the combustion gas release was important as well as the timing to inject the nitrogen gas. The valve timing was controlled according to the chamber pressure. Three-time cyclic combustion-mode transitions were accomplished.

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