The enthalpies of combustion and enthalpies of formation of three trinitromethyl derivatives of 1,3,5-triazine are determined by the calorimetric method. The data obtained can be used for calculating the energy capabilities of related compounds by the method of replacing functional groups. As an example, the detonation characteristics of high-energy tris(trinitromethyl)-1,3,5-triazine are calculated.

The possibilities of increasing the acceleration ability (AA) of energetic materials by creating compositions combining high explosives (HEs) with a positive and negative oxygen balance are analyzed. For the calculations, three relatively new compounds are selected as HE-oxidizers: 3,6-dinitro-1,4-bis(trinitromethyl)-1,4-dihydropyrazolo[4,3-c]pyrazole; 4,4′5,5′-tetranitro-2,2′-bis(trinitromethyl)-2Н,2′Н-3,3′-bipyrazole; and 2-dinitromethyl-5-nitrotetrazole. HMX and CL-20 perform the function of HE-fuel. From the calculations it follows that the AA of HMX increases markedly with the addition of the mentioned oxidizers, and the introduction of oxidizers in the composition with CL-20 leads to a slight increase in AA.

The results obtained show that the addition of aluminum (Al) and aluminum hydride (AlH3) to an explosive significantly increases the heat of an explosion (HE) and the TNT equivalent (TE) of an underwater explosion. The compositions with AlH3 are inferior to their Al-containing counterparts in the HE. However, the formulations with AlH3 have the advantage in terms of the number of moles of gaseous products. Replacing Al with AlH3 weakly affects the TE in terms of the energy of a gas bubble, while the TE in terms of the energy of a shock wave is higher for the mixtures with AlH3. The latter is especially noticeable in the case of an explosive with a positive oxygen balance. However, the compositions with AlH3 are inferior to the Al-containing mixtures in terms of volumetric TE.

Разработаны эмпирические формулы для оценки тротилового эквивалента (ТЭ) подводного взрыва по энергии ударной волны (УВ) и по энергии газового пузыря (ГП). Метод расчета основан на использовании калориметрических значений теплоты взрыва (ТВ). Соотношения получены статистической обработкой массива данных, включающего значения ТЭ как для взрывчатых материалов (ВМ), не содержащих алюминий (Al), так и для алюминизированных композиций. Выполнены оценки ТЭ подводного взрыва для ряда смесей взрывчатых веществ (ВВ) c порошкообразным алюминием. Наибольший эффект от введения Al получен для ВВ с положительным кислородным балансом (КБ). Расчеты показали отсутствие преимуществ по ТЭ подводного взрыва у композиций с наноразмерным Al перед составами с микроразмерным Al.

Analysis of the published data showed that the detonation characteristics of the dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate diolate explosive material (TKX-50) are estimated by the authors of a number of publications based on the overestimated calculated value of the standard enthalpy of the formation of this compound. At the Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences (FRC CP RAS), a significantly lower value of the enthalpy of formation of TKX-50 is obtained by the carefully performed calorimetric measurements. This value is used to calculate the detonation velocity and pressure, heat of the explosion, and propelling power of TKX-50. From the results of the assessments it follows that the considered compound belongs to the category of explosives with moderate potency.

It is known that, under strong shock wave loading or at high temperatures, polytetrafluoroethylene (PTFE) decomposes and forms chemically active products that are capable of interaction with metals. In this work, data on the heat of explosion of mixtures containing HMX, PTFE, and Al are given. From the results, it follows that aluminized explosive compositions are characterized by high values of the heat of explosion. The high temperatures that develop at the formation of aluminum oxide promote PTFE decomposition. However, the heat of an explosion decreases as PTFE concentration increases. This is because PTFE has a strongly negative heat of formation. The evaluation of the acceleration ability shows that PTFE can be used in explosive formulations, intended for the accelerating action, on condition that the composition contains a high explosive with a positive oxygen balance.

The results of investigating the heat from the explosion of individual and aluminized blasting compounds shows that, when testing an unconfined charges, the explosion’s products undergo intense secondary heating when they reach the wall of the calorimetric bomb’s inner cavity. Due to the secondary heating in the products, the chemical reactions are resumed, and the final composition of the products is frozen in conditions of slow cooling and low pressure. The inert metal casing in which a charge is placed attenuates the secondary heating since a significant part of the energy of the products is converted into the kinetic energy of the casing. The effect of filling a calorimetric bomb with an inert gas is similar to the action of a metal casing. In this case, the secondary heating temperature decreases due to the heat spent on heating the inert gas. When testing aluminized compositions, we need to use a heavy casing and fill the bomb with an inert gas (under pressure) in order to reduce the temperature of the secondary heating. The heat of explosion (HE) obtained under conditions when the secondary heating temperature does not reach the threshold value can be considered as a universal parameter that characterizes the energy content of an explosive material.

Detonation calorimetry studies have shown that the addition of a silicon nanopowder (n-Si) to HMX leads to a significant increase in the heat of explosion. However, the heat of explosion of composites with n-Si is lower than that of composites containing boron and aluminum (particularly aluminum nanoparticles). Combustible additives have been arranged in orders taking into account their effect on the energy content of the explosive.

Results of a study of explosives with varying oxygen balance by a method based on the acceleration of a steel plate from the charge end face (M-40) have confirmed the possibility of increasing the acceleration ability of these substances owing to the addition of powdered aluminum. The experimental and calculated data suggest that, in the case of mixtures prepared by the conventional method of mechanical mixing, compositions with aluminum nanoparticles and compositions containing aluminum with a particle size on the order of a few microns have similar acceleration ability values. Nanocomposites—systems with a uniform distribution of aluminum nanoparticles in the explosive matrix—can be superior to the mechanical mixtures in acceleration ability in the case of a highly negative oxygen balance of the explosive base. Calculations have shown that the acceleration ability of mixtures of low-sensitivity explosives with aluminum can be further increased owing to the formation of nanocomposites.

Experimental results have shown that the use of inorganic oxidizers (ammonium nitrate, ammonium perchlorate, and ammonium dinitramide) as additives does not lead to a considerable increase in the heat of explosion and acceleration ability of HMX. Ammonium perchlorate does not have an effect on the acceleration ability; however, it leads to an increase in the heat of explosion of triaminotrinitrobenzene. Calculations have shown that the acceleration ability of explosives with a low oxygen ratio can be increased through the formation of nanostructured composites with inorganic oxidizers. Calculations suggest that the addition of the studied oxidizers to CL-20 leads to a decrease in the acceleration ability of this promising explosive.

The results of the studies performed show that the introduction of powdered boron and aluminum into high explosives increases the heat of explosion and acceleration ability. Aluminized compositions are demonstrated to be superior to boron-containing mixtures in these parameters. The greatest gain in the acceleration ability can be obtained by using nanoaluminum with particles coated by a protective layer of an active material.

The heat of explosion of composites containing HMX and nanosized aluminum in a mass ratio of 85/15 has been studied by detonation calorimetry. Powders of nanoaluminum, mechanical mixtures, and nanocomposites have been stored in an unsealed container at room temperature under conditions of natural humidity for 18 months. The test results have shown that the heat of explosion of separately stored nanoaluminum decreases to a lesser extent than in the case of contact between the nanoaluminum and HMX during the storage of the composites. The most significant decrease in the heat of explosion is observed for the composites with the smallest nanoaluminum particles. The derived data have been used to analyze the effect of aging on the acceleration ability of the composites.

New experimental data on detonation wave parameters and explosive performance for benzotrifuroxan are presented. Optical pyrometry was applied in order to measure the temperature and pressure of BTF detonation products. Chapman-Jouguet temperature was obtained as 3990 – 4170 K (charge densities 1.82 – 1.84 g/cc). The heat of explosion and the acceleration ability were measured also. It is also considered the hypothesis of formation of nanodiamond particles in detonation products directly behind the detonation front and influence of these processes on the temperature-time history in detonation products.

Measurements and calculations of the heat of explosion and acceleration ability of aluminized compositions based on hexanitrohexaazaisowurtzitane, a promising high explosive, showed that the indicated parameters of such mixtures substantially exceed those of HMX-based counterparts. Creating aluminized nanocomposites to improve the acceleration ability is advantageous only if the content of the oxide film in the nanoaluminum powder is minimized by coating the particles with a protective layer of an active material. According to calculations, nanocomposites containing hexanitrohexaazaisowurtzitane and aluminum with active coating should have a record acceleration ability.