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1

Comparative Theoretical Investigation on Energetic Substituted Furazanyl Ethers

Liu N., Wang K., Shu Y., Zeman S., Wang B., Wang W.

Central European Journal of Energetic Materials

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2018

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Vol. 15, no. 1

47--71

EN

Furazanyl ether has great potential to be an important candidate as a casting explosive and energetic plasticizer. The density functional theory (DFT) method was used to investigate the heats of formation (HOFs), molecular stability, detonation performance and melting point of a series of substituted furazanyl ethers at B3LYP/6-311G(d,p) level. The results show that the introduction of –N3 or –N(O)=N– groups significantly improves the HOFs values of the derivatives. The bond dissociation energies (BDEs) were analyzed, showing that the N–O bond in the furazan ring is the weakest for most compounds and the ring is vulnerable to cleavage in thermal decomposition. The calculation of density, detonation velocities and detonation pressures suggests that the substitution of –NF2, –CF(NO2)2, furoxan or –N(O)=N– group is an effective method for enhancing their detonation performance. The melting points were determined according to the variation of specific heat capacity, and good estimates were obtained in comparison with the available experimental data. Taking into account the detonation performance and melting point, four compounds are favoured for application in melt cast explosive or energetic plasticizers.

2

Application of BCHMX in Shaped Charges against RHA Targets Compared to Different Nitramine Explosives

Elbeih A., Elshenawy T., Zeman S., Akstein Z.

Central European Journal of Energetic Materials

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2018

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Vol. 15, no. 1

3--17

EN

In this work, a new bicyclic nitramine, cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5-d]imidazole (bicyclo-HMX or BCHMX), has been tested for its performance as a shaped charge explosive filler in comparison with three other interesting cyclic nitramines. Four shaped charges were prepared using different nitramine-based plastic bonded explosives (PBXs), and their performance was measured experimentally in terms of the penetration depth into laminated rolled homogeneous armour (RHA) targets. The explosive fillers were highly pressed PBXs based on RDX, HMX, BCHMX and CL-20, bonded by Viton A binder. The Autodyn numerical hydrocode was implemented to determine the shaped charge jet’s characteristics and its penetration depth. The experimental and calculated detonation characteristics of the explosives used are reported. Relationships between the detonation characteristics of the explosives and the jet characteristics were observed. The results show that CL-20 is the most powerful explosive, with the largest penetration depth into the RHA target, while BCHMX explosive has a relatively enhanced penetration depth with respect to RDX explosive. The results of the Autodyn code calculations are consistent with the experimental measurements, with a maximum difference of 6.6%.

3

Relative Explosive Strength and Detonation Characteristics of Some Explosive Mixtures Containing Urea and Peroxides

Hussein A. K., Zeman S., Suceska M., Jungova M.

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2017

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Vol. 8, Nr 3 (29)

23--32

EN

Several mixtures, based on urea, urea hydrogen peroxide complex (UHP), triacetone triperoxide (TATP) with some inorganic oxidants were studied by means of ballistics mortar with TNT as a reference standard. The detonation pressure, P, detonation velocity, D, detonation heat, Q, and volume of gaseous product at standard temperature and pressure conditions (STP condition) were calculated by the mean of Explo5 V6.3. The relatively high explosive strength of some samples relative to the TNT charge, focuses on the positive influence of hydrogen peroxide presence in these mixtures, with advantage in the form of its complex with urea (i.e. as UHP). This influence connects with hydroxi-radical in the mixture under its initiation (as the first intermediate of this initiation reaction).

4

Concerning the Shock Sensitivities of Certain Plastic Bonded Explosives Based on Attractive Cyclic Nitramines

Zeman S., Elbeih A. E., Hussein A., Elshenawy T., Pelikán V., Yan Q-L.

Central European Journal of Energetic Materials

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2017

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Vol. 14, no. 4

775--787

EN

Plastic bonded explosives (PBXs) based on ε-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (ε-HNIW), 1,3,5-trinitro-1,3,5-triazinane (RDX), β-1,3,5,7-tetranitro-1,3,5,7-tetrazocane (β-HMX) and cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5-d]imidazole (BCHMX) were prepared using a hydroxyl-terminated polybutadiene as a binder (HTPB) and cured with hexamethylene di-isocyanate (HMDI). Recently published data for analogous PBXs with a polyisobutylene binder (i.e. a C4 matrix) are also included. All of these PBXs were tested using the Small Scale Water Gap Test according to STANAG 4490, the results of which are directly proportional to the impact and friction sensitivities of the PBXs studied. Reciprocal ratios between the shock sensitivity of these PBXs and their performance were found using the volume heat of explosion as a variable; a semi-logarithmic analogue, using a representative of the detonation pressure (product ρD2) as a variable, has shown an opposite trend for three of these PBXs. A semi-logarithmic relationship between the shock sensitivity of the PBXs and the impact sensitivity of their pure nitramine fillers has confirmed the higher shock reactivity of the C4 PBXs filled with both technical ε-HNIW and RS-ε-HNIW, while for the HTPB PBXs filled with technical grade ε-HNIW, the shock sensitivity found was as expected. The shape and size of the particles should not be a reason for the increased resistance to shock of HMX-C4.

5

4,6-Diazido-N-(2,4,6-trinitrophenyl)-1,3,5-triazin-2-amine (TNADAzT) and Its Silver Salt − Synthesis and Characterization

Musil T., Matyáš R., Zeman S., Růžička A., Lyčka A., Majzlík J., Vala R., Knotek P.

Central European Journal of Energetic Materials

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2017

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Vol. 14, no. 2

304--320

EN

4,6-Diazido-N-(2,4,6-trinitrophenyl)-1,3,5-triazin-2-amine (TNADAzT) and its silver salt (AgTNADAzT) were prepared and characterized. Elemental analysis, FTIR, NMR, DSC, AAS and X-ray diffraction were used for analytical characterization. The sensitivities of TNADAzT and AgTNADAzT were determined and compared with common explosives and MTX-1. The crystal density of TNADAzT is 1.794 g·cm−3 and its heat of formation 899 kJ·mol−1. The sensitivity of TNADAzT to impact and friction slightly exceeds PETN; the sensitivity to electrostatic discharge is lower than RDX. The sensitivity of AgTNADAzT is on the level of a primary explosives (between mercury fulminate and PETN). The initiation efficiency of AgTNADAzT is higher than 200 mg (acceptor PETN compressed by 64-70 MPa) and therefore excludes it from practical use as a primary explosive in detonators.

6

Recent Advances in the Study of the Initiation of Nitramines by Impact Using Their 15N NMR Chemical Shifts

Jungová M., Zeman S., Yan Q.-L.

Central European Journal of Energetic Materials

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2014

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Vol. 11, no. 3

383--393

EN

The relationship between the 15N NMR chemical shifts of aza nitrogen atoms in twelve nitramines and the impact sensitivity of these compounds, expressed as the drop energy, Edr, has been analyzed from the point of view of recently published findings. This relationship appears to be the best method for identifying the key atoms at the reaction centre of a given molecule. These atoms might be taken as “chemical hot spots”. The absence of any solid state influence on the chemical shifts, which were here determined in solution, does not have a fundamental influence on the reaction centre identification. The relationship discussed here confirms the close molecular structural dependence for drop energies (impact sensitivities) obtained for individual energetic materials (EMs) by means of a standard impact tester (Julius Peters) with the detection of the 50% probability of initiation based on acoustic detection. The dependence of impact sensitivity on specific crystal surfaces, using samples of individual EMs obtained by screening, should be investigated more extensively.

7

Recent advances in the study of the initiation of energetic materials rusing characteristics of their thermal decomposition. Part I, Cyclic nitramines

Zeman S., Yan Q.-L., Vlček M.

Central European Journal of Energetic Materials

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2014

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Vol. 11, no. 2

173--189

EN

Arrhenius parameters, Ea and log A, of 17 cyclic nitramines, derived from the Russian vacuum manometric method (SMM) and compatible thermoanalytical methods, have been used in this study. The detonation velocity, D, at maximum theoretical crystal density, of the nitramines in this study was taken as a characteristic of their detonation. On the basis of known relationships between their Ea and D2 values (modified Evans-Polanyi-Semenov equation), the specific influence of some physicochemical properties on their thermal decomposition was shown. A new logarithmic relationship was found between the rate constant k, of the unimolecular thermal decomposition of the nitramines studied at 230 °C, and their D values. A fundamental characteristic of this new relationship rests on the equivalency of the primary fission processes in the low-temperature thermal decomposition and on the detonation initiation of the nitramines under study. Both these relationships confirm the problems encountered in the kinetic specification of the thermal decomposition of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12hexaazaisowurtzitane (HNIW, CL-20) and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX). These problems, and also the possible influence of the pre-decomposition states on the thermal decomposition of the nitramines studied, are discussed.

8

Recent Advances in the Study of the Initiation of Energetic Materials Using the Characteristics of Their Thermal Decomposition Part II. Using Simple Differential Thermal Analysis

Zeman S., Yan Q.-L., Elbeih A.

Central European Journal of Energetic Materials

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2014

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Vol. 11, no. 3

395--404

EN

Simple Differential Thermal Analysis (DTA), with evaluation of its output by the Kissinger method, was used in the case of emulsion explosives and, as an advanced application, for several plastic bonded explosives (PBXs). In both of these kinds of explosive the square of their detonation velocities, D2, is used as their performance characteristic. A relationship between the slope of the Kissinger equation, EaT-1, and the D2 values makes it possible to formulate a possible mechanism for the initiation of emulsion explosives. Regarding PBXs, it would seem possible to postulate a change in the detonation chemistry of plastic bonded nitramines, depending on the pressure and temperature in the zone of the detonation wave, particularly in the case of CL-20 fillers. Binders with aromatic building units in their macromolecular structure seem to be less-favoured in terms of their thermal reactivity and performance than the final PBXs. These findings document the advantages of the above-mentioned application of simple DTA.

9

Concerning the shock sensitivity of cyclic nitramines incorporated into a polyisobutylene matrix

Pelikán W., Zeman S., Yan Q. L., Erben M., Elbeih A., Akštein Z.

Central European Journal of Energetic Materials

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2014

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Vol. 11, no. 2

219--235

EN

Two types of plastic bonded explosives (PBXs) based on ε-2,4,6,8,10,12hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (ε-HNIW, CL-20), and PBXs based on 1,3,5-trinitro-1,3,5-triazinane (RDX), β-1,3,4,7-tetranitro-1,3,5,7-tetrazocane (β-HMX) and cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5-d]imidazole (bicycloHMX, BCHMX) were prepared using a polyisobutylene binder with dioctylsebacate (DOS) as plasticizer, i.e. a C4 matrix. One version of the ε-HNIW PBX is a product with reduced sensitivity (RS-ε-HNIW). All these PBXs, referenced respectively as RS-ε-HNIW-C4, ε-HNIW-C4, RDX-C4, HMX-C4 and BCHMX-C4, were tested using the Small Scale Gap Test according to STANAG 4488. The results of the gap test on the PBXs with RDX, β-HMX and BCHMX correspond to the impact sensitivities of the original crystalline nitramines. This is not entirely valid for ε-HNIW. In other words, PBXs with RS-ε-HNIW cannot achieve as low a shock sensitivity as would be expected from the differences obtained from the impact sensitivities between RDX, β-HMX and BCHMX, on the one hand, and RS-εHNIW on the other. It is shown that the morphological stability of RS-ε-HNIW in the C4 matrix is insufficient. However, further development and use of RS-ε-HNIW as a filler of PBXs would seem to be both desirable and beneficial. Despite the relatively high impact sensitivity of crystalline BCHMX, the shock sensitivity of its analogous C4 PBX is already good, and comparable with that of RS-ε-HNIW.

10

Characteristics of Melt Cast Compositions Based on cis-1,3,4,6-Tetranitrooctahydroimidazo-[4,5 d] imidazole (BCHMX)/TNT

Elbeih A., Zeman S.

Central European Journal of Energetic Materials

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2014

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Vol. 11, no. 4

501--513

EN

cis-1,3,4,6-Tetranitrooctahydroimidazo-[4,5 d]imidazole (BCHMX) is a new bicyclic nitramine which has been prepared using a two-stage synthetic method. In this work, a new melt cast composition based on BCHMX/TNT (60/40 by wt.) was prepared. For comparison purposes, Composition B based on RDX (1,3,5-trinitro1,3,5-triazacyclohexane)/TNT (60/40 by wt.), and HMX (1,3,5,7-tetranitro-1,3,5,7tetraazacyclooctane)/TNT (60/40 by wt.) were also studied. Impact and friction sensitivities of these compositions and of the individual explosives were determined. The detonation velocities were measured experimentally. The performance of the compositions prepared was studied by measuring the brisance using the Kast method. The detonation parameters of the compositions and the individual explosives were calculated using the EXPLO5 thermodynamic code. The results show that mixing these nitramines with TNT decreases their sensitivities. BCHMX/TNT is more sensitive to impact and friction than Composition B while it has higher detonation parameters, at the same level as HMX/TNT. In comparison, BCHMX/TNT has the highest relative brisance of the compositions studied. It is postulated that the higher performance characteristics of BCHMX and compositions based on it, in comparison with those of HMX, are due to a higher positive heat of formation for this nitramine.

11

Some Relationships Among Thermal Properties, Detonation Parameters and Sensitivity of Nitramine Fillers in Formex Based PBXs

Yan Q. L., Zeman S., Elbeih A.

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2013

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Vol. 4, Nr 2 (12)

7-17

EN

Thermal behavior and decomposition kinetics of formex-bonded on some attractive cyclic nitramines (BCHMX, HMX, RDX and CL-20) were investigated by means of nonisothermal Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC). Besides, their detonation parameters have been calculated by EXPLO 5 code. It was found that the effect of formex polymer base on thermal decomposition of HMX is different from other cyclic nitramines, namely, the formex base could increase the activation energy of HMX while decrease that of others. Besides, the logarithm of volume heat of detonation for formex based explosives is linearly dependent on their time constant of initiation. Furthermore, on one hand, except for RDX, the heat of detonation decreases with the increase of activation energy, and the spark energy and impact energy of cyclic nitramine fillers decreases with the increase of the critical temperature of their PBXs. On the other hand, except for HMX, the rate constant of PBXs is linearly dependent on the impact sensitivity of their pure nitramine fillers.

12

The Influence of the Semtex Matrix on the Thermal Behavior and Decomposition Kinetics of Cyclic Nitramines

Yan Q. L., Zeman S., Elbeih A., Zbyněk A.

Central European Journal of Energetic Materials

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2013

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Vol. 10, no. 4

509--528

EN

The thermal behavior and decomposition kinetics of Semtex 10 polymeric matrix (Semtex) bonded PBXs containing RDX (1,3,5-trinitro 1,3,5-triazinane), HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocane), BCHMX (cis-1,3,4,6tetranitrooctahydroimidazo [4,5-d] imidazole), HNIW (2,4,6,8,10,12-hexanitro2,4,6,8,10,12-hexaazaisowurtzitane) have been investigated by means of nonisothermal TG and DSC techniques. It is shown that only a single decomposition process occurs for RDX-SE and HMX-SE whilst an obvious two-step process occurs for CL-20-SE and BCHMX-SE. The onset of the exotherms were observed at 210.6, 239.7, 279.2 and 229.4 °C with the peak maxima at 232.2, 249.4, 280.4 and 240.2 °C, and energy changes of 1808, 2140, 612 and 1757 J·g-1 for RDX-SE, BCHMX-SE, HMX-SE and CL-20-SE, respectively. It has been found that the Semtex matrix has little influence on the activation energy distribution for RDX, BCHMX and ε-CL-20. The activation energies for BCHMX-SE and CL-20-SE decomposition are almost independent of the degree of conversion, with mean values of 159.6 ±1.9 and 187.3 ±1.8 kJ·mol-1. It has been proved that Semtex and Viton A are better binders than C4 and Formex for ε-CL-20 and RDX based PBXs in terms of their greater thermal stability, and Formex is a poor binder for BCHMX.

13

Effect of polar plasticizers on the characteristics of selected cyclic nitramines

Elbeih A., Zeman S., Pachman J.

Central European Journal of Energetic Materials

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2013

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Vol. 10, no. 3

339--349

EN

Dioctyl sebacate (DOS) is a plasticizer used with oily material for the softening of polyisobutylene binder (PIB) to form a polymeric matrix. This matrix was used for the preparation of various plastic explosives. The following energetic cyclic nitramines were used as explosive fillers: BCHMX (cis-1,3,4,6- tetranitrooctahydroimidazo [4,5 d]imidazole), ε-HNIW (ε-2,4,6,8,10,12- hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane), RDX (1,3,5-trinitro-1,3,5- triazacyclohexane), and HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane). For comparison, Fluorel binder was used for the preparation of several plastic bonded explosives (PBXs) based on the same selected explosives. Impact and friction sensitivities of the prepared samples and the pure explosive fillers were measured. The thermal stability was studied using differential thermal analysis (DTA). High performance liquid chromatography (HPLC) was used to detect the presence of BCHMX dissolved in dioctyl sebacate (DOS). The heat of combustion of the prepared samples and of the pure explosive fillers was measured using a bomb calorimetry. The results show that PIB softened by plasticizer (DOS) has a greater positive effect on decreasing the impact sensitivity of the studied pure explosives than Fluorel binder. On the other hand, the plasticizer acts as a solvent for the energetic materials and decreases the decomposition temperature of these plastic explosives.

14

Evaluation of Oxygen Permeability of Polyethylene Films

Zeman S., Kubík L.

Technical Sciences / University of Warmia and Mazury in Olsztyn

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2012

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nr 15(2)

331-345

EN

The paper dealt with the evaluation of the oxygen permeability of the polyethylene films applied in the mulching and food packaging. The construction of the equipment is discussed. The design and the construction of the equipment was realized with applying of the standard EN STN 77 0333.The measurement of the permeability of the oxygen trough the polyethylene Bralen 2-63 with 9% colored concentrate Maxithen HP 533041 - violet film was realized by means of modified method. The values of the permeability Px, 1794.25 cm3*m-2*d-1. (0.1 Mpa)-1 of the oxygen trough the film of the thickness of 50 µm was evaluated. The coefficient of permeability P, 4.2560*10-16 mol*m-1*s-1*Pa-1, coefficient of diffusion D, 4.3999*10-10 m2*s-1 and solubility coefficient of the gas in the film Sp, 9.6735*10-7 mol*m-3*Pa-1 were determined.

15

Effect of Different Polymeric Matrices on the Sensitivity and Performance of Interesting Cyclic Nitramines

Elbeih A., Zeman S., Jungova M., Akstein Z.

Central European Journal of Energetic Materials

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2012

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Vol. 9, nr 2

131-138

EN

Different polymeric matrices, based on butadiene-styrene rubber, polymethyl-methacrylate and silicone binders, were investigated for their ability to decrease the sensitivity of explosives to different mechanical stimuli. A series of plastic explosives based on four different nitramines, namely RDX (1,3,5-trinitro- 1,3,5-triazacyclohexane), β-HMX (β-1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane), BCHMX (bicycloHMX, cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5- d ]imidazole) and ε -HNIW (ε -2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane, ε-CL-20), bonded by the selected polymeric matrices were prepared. Sensitivity to impact of all of the plastic explosives prepared as well as of the pure explosives, was measured using the fall hammer test. Sensitivity to friction was determined using the BAM friction test. The performance was studied using the ballistic mortar test and the results were recorded relative to TNT (trinitrotoluene) as reference. By comparing the results of impact and friction sensitivities, it is obvious that the mechanism of transfer of the friction force to the reaction center of the nitramine molecule should be different from that of impact energy transfer. The silicone binder appeared to be the best polymer for decreasing the sensitivity of explosives. The results of the ballistic mortar proved that the performance of the plastic explosives prepared is affected by the type and weight percentage of the binder in each sample.

16

Path to ε-HNIW with Reduced Impact Sensitivity

Elbeih A., Husarova A., Zeman S.

Central European Journal of Energetic Materials

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2011

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Vol. 8, nr 3

173-182

EN

New purification method was applied to obtain epsilon HNIW (ε-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane, ε-HNIW) which has low impact sensitivity. The method is based on removing the impurities from a solution of alpha HNIW (ε-HNIW) by a chemical reaction to obtain pure epsilon form. For comparison, selected different published methods for recrystallization of HNIW to obtain the epsilon form were studied. All the selected methods are based on solvent-antisolvent technique. The optimum parameters, such as type of solvent and anti-solvent, volume ratio of solvent to anti-solvent, rate of addition, speed of stirring, etc., were applied to enhance the crystal size and shape of ε-HNIW. Checking the polymorphs of the obtained HNIW was done by Fourier transform infrared spectroscopy (FTIR). The thermal stability of the prepared samples was studied by using differential thermal analysis technique (DTA). Qualitative analysis of the crystal size and shape was done using scanning electron microscope (SEM) devise. Quantitative measurement of the crystals sizes for the studied samples was determined by Laser scattering particle size distribution analyzer. Impact sensitivity was measured by falling hammer test. The results indicate that all the applied methods of recrystallization give ε-HNIW. The impact sensitivity of HNIW decreases by obtaining small particles with regular shape. All the used published methods produce ε-HNIW with higher impact sensitivity than other nitramines. While the obtained crystals from the new method has regular smooth surface, with small particle size and its impact sensitivity is lower than RDX and HMX.

17

Fortifcation of W/O Emulsions by Demilitarized Explosives. Part I. Use of TNT

Němec O., Jungová M., Mareček R., Novotný M., Zeman S., Šelešovský J.

Central European Journal of Energetic Materials

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2011

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Vol. 8, nr 3

193-207

EN

This paper presents a study of the relationship between detonation velocities, D, and relative explosive strength (RS) of fortifed W/O emulsion explosives, on the one hand, and the grain size and quality of the demilitarized TNT used for this fortifcation, on the other. It has been found that demilitarized TNT having a grain size below 400 μm could give acceptable results both in terms of initiation and detonation velocity and the RS values. Demilitarized TNT, however, is not a reliable sensitizer even in a micronized state, and therefore using TNT necessitates simultaneous sensitizing of the fnal W/O explosive with microballoons and it has no signifcantly better infuence on the performance of the resulting explosives. The small-scale cook-off test of such a W/O mixture fortifed by 50% by wt. of TNT has shown that such a mixture is a relatively safe explosive.

18

Replacement of PETN by Bicyclo-HMX in Semtex 10

Elbeih A., Pachman J., Zeman S., Akstein Z.

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2010

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Vol. 1, Nr 2 (2)

7-16

EN

Bicyclo-HMX (BCHMX) was studied in the form of a plastic explosive bonded by the plastic matrix of the explosive Semtex 10 and the results were compared with the original Semtex 10 which contains PETN as an explosive filler. The tests included measurements in the sensitivity to impact and friction. The thermal stability was studied using differential thermal analysis (DTA) with the evaluation of the outputs using the Kissinger method. The detonation velocity was measured experimentally and the detonation characteristics were calculated by means of EXPLO 5 code and the Kamlet & Jacobs method. On the basis of mutual comparison of all the obtained results, it was concluded that replacement of PETN by Bicyclo-HMX enhances the friction sensitivity, thermal stability and the detonation parameters of the explosive Semtex 10, while the impact sensitivity is approximately the same. Calculated results of EXPLO 5 code showed good agreement with the experimental detonation velocities.

19

Thermal Stability and Detonation Characteristics of Pressed and Elastic Explosives on the Basis of Selected Cyclic Nitramines

Elbeih A., Pachmáň J., Zeman S., Trzciński W. A., Akstein Z., Sućeska M.

Central European Journal of Energetic Materials

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2010

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Vol. 7, nr 3

217-232

EN

Bicyclo-HM X (cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5-d] imidazole or BCHM X) was studied as a plastic explosive bonded with the C4 matrix and with Viton A. Also a series of nitramines namely RDX (1,3,5-trinitro-1,3,5=triazinane), HM X (1,3,5,7-tetranitro-1,3,5,7-tetrazocane) and HNIW (ĺ-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane, ĺ-CL-20) were studied for comparison with the same types of binders. The detonation velocity, D, of all prepared mixtures was measured. Their thermal stability was determined using non-isothermal differential thermal analysis (DTA). While the C4 matrix lowers the thermal stability of the resulting explosives, Viton A enhances this stability. Approximate relationships between the peaks of exothermic decomposition and the D values were found. The detonation parameters were also calculated by means of Kamlet & Jacobs method, CHEETAH and improved EXPLO5 code for all the mixtures. From the measured D values and the calculated detonation parameters, it is obvious that the detonation parameters of BCHM X-mixtures are very close to HM X-explosives and better than those of RDX-mixtures. It was found that the C4 matrix reduces the difference between the values of energy of detonation in the studied C4 mixtures. As expected, the pressed HNIW-Viton A mixture has the highest detonation parameters of all of the prepared mixtures.

20

Contribution to the Synthesis of 4,10-Dinitro-2,6,8,12-tetraoxa-4,10-diazatetracyclo[5.5.0.05,903,11]dodecane (TEX)

Jalový Z., Matyáš R., Klasovitý D., Zeman S.

Central European Journal of Energetic Materials

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2010

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Vol. 7, nr 3

189-196

EN

The influence of the reaction conditions on 4,10-dinitro-2,6,8,12-tetraoxa- 4,10-diazatetracyclo[5.5.0.05,903,11]dodecane (TEX) yield was studied. TEX was prepared by the reaction of 1,4-diformyl-2,3,5,6-tetrahydroxypiperazine with glyoxal in nitric acid. The influence of the acidity of reaction mixture and ratios of starting materials on the yield of TEX was examined and synthesis was optimised. The highest yield (37%) was obtained at 1,4-diformyl-2,3,5,6-tetrahydroxypiperazine/nitric acid molar ratio 67 and sulfuric acid/nitric acid molar ratio around 0.15. Starting material 1,4-diformyl-2,3,5,6-tetrahydroxypiperazine was prepared from formamide and glyoxal using triethylamine or other tertiary amines to adjust suitable basicity. The best yield (84%) of 1,4-diformyl-2,3,5,6-tetrahydroxypiperazine was reached at molar ratio triethylamine/formamide equal to 0.1.