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1

A New Testing Method for the Mechanical Properties of Elastic Explosive Compositions

Powała Dorota, Nita Marcin, Orzechowski Andrzej, Maranda Andrzej

Central European Journal of Energetic Materials

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2021

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Vol. 18, no. 4

545--569

EN

In recent years, Polymer Bonded Explosives (PBX) have been used in a wide variety of military applications. Many different kinds of polymers are used for such explosive formulations. This component determines both the preparation method and the properties of a PBX. In this paper, results are presented of studies on the preparation and testing of explosive compositions based on pentaerythritol tetranitrate (PETN, penthrite) and silicone rubber. These studies were undertaken to obtain elastic formulations of PBXs. Therefore, the possibility of applying a silicone rubber as a component of the composition was checked. In the first stage of this study, several compositions were prepared in order to choose the optimal mixture ratio with respect to cohesion of the explosive. For this purpose, a new method using the Brookfield Texture Analyser was developed. Subsequently, compatibility tests using thermal analysis methods were carried out. The best of composition was subjected to tests for determining its physicochemical and explosive characteristics.

2

Hydroxyl Terminated Polybutadiene: Chemical Modification and Application of these Modifiers in Propellants and Explosives

Zhang Qian, Shu Yuanjie, Liu Ning, Lu Xianming, Shu Yao, Wang Xiaochuan, Mo Hongchang, Xu Minghui

Central European Journal of Energetic Materials

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2019

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Vol. 16, no. 2

153--183

EN

Hydroxyl terminated polybutadiene (HTPB) as a telechelic liquid polymer has been widely used in propellants and explosives and many modified-HTPBs have been reported in the literature. As a binder or additive in propellants and explosives, the chemical modification of HTPB for improving certain properties of propellants has been summarized in detail in this article. According to the application drawbacks of HTPB, modified-HTPB can be classified differently. Furthermore, there are polymers that have been modified on their energetic properties, such as GAP-PB-GAP, BAMO-PB-BAMO, AMMO-PB-AMMO, Nitro-HTPB, HTPB-DNB and NHTPB. Pre-polymers modified on their combustion properties include Butacene®, FPDS-g-HTPB, Fc-HTPB, BiFc-g-HTPB, HTPB→[Fe(CO)3]x, PPA-HTPB-PPA and PNBE-HTPB-PNBE. HTPBs are also modified in curing systems containing, for example ETPB, PTPB, PrTPB, AzTPB, and PUPB, and other modification results are reviewed. Additionally, this overview is expected to provide an outlook for further studies in these fields.

3

An analysis of signaling in a hybrid WebRTC and SIP environment

Chodorek R. R., Rzym G., Wajda K., Chodorek A.

Studia Informatica

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2018

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Vol. 39, nr 1

5--14

EN

The paper describes a complete voice communication system based on the implementation of Asterisk software PBX and additionally employing classical SIP, and novel WebRTC solutions to create a signaling system. The implementation presented explores many functions of the system with an emphasis on enhancing its didactic impact and promoting understanding of configuration and signaling aspects.

PL

W artykule przedstawiono kompletny system komunikacji głosowej wykorzystujący zarówno programową centralę Asterisk, jak i jednocześnie dwa systemy sygnalizacji: klasyczny SIP i nowy stosowany w technologii WebRTC. Przedstawione rozwiązanie wykorzystuje jednocześnie wiele funkcji systemów, pozwalając na wyeksponowanie istotnych z punktu widzenia dydaktyki aspektów budowy systemów VoIP.

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

Studies on Tungsten Based High Density Cast Polymer Bonded Explosive (PBX) Formulations

Vadhe P. P., Manickam S., Rahujade N., Kondra A., Prasad U., Sinha R. K.

Central European Journal of Energetic Materials

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2015

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Vol. 12, no. 3

497--506

EN

Aluminized melt-cast TNT and PBX (cast/pressed) based compositions have been widely studied and used in different warheads for various applications,such as air blast, underwater blast, thermobaric effects, etc. Tungsten (W) based cast PBX formulations are the least reported in the literature. We have partially replaced RDX or HMX in the control PBX formulation with 15 to 25% W powder and investigated the effect of this on the ease of processing, density, sensitivity, mechanical properties and explosive performance. The viscosity was improved from 9 to 3 kPoise, and the density by about 12 to 25% on the addition of W powder to the PBX formulations. The sensitivity to impact for the RDX/Wand HMX/W based PBX formulations was improved by 12 to 37%. The reinforcing effect of the W powder caused an increase in hardness (Shore A) by 16 to 45%. A decreasing trend in the velocity of detonation (VOD) was observed because of the replacement of the nitramine content (RDX/HMX) with W powder. The approximate detonation pressure of RDX/W/HTPB (65/20/15), roughly calculated by the Kamlet-Jacobs method, is better than the other tungsten based formulations investigated.

6

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.

7

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.

8

Recent trends in research on energetic materials at Cambridge

Proud W. G., Walley S. M., Williamson D. M., Collins A. L., Addiss J. W.

Central European Journal of Energetic Materials

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2009

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Vol. 6, nr 1

67-102

EN

Recent work in our laboratory has established a time-temperature superposition law for a PBX. This was achieved by performing uniaxial compression testing over a wide range of strain rates and temperatures along with Differential Thermal Mechanical Analysis (DMTA). The classic WLF (Williams, Landel, Ferry) transform was found not to fit the shift factor needed to align the data whereas a simple log-linear fit did. The thermal properties (diffusivity, conductivity, heat capacity) of a PBX have been measured three different ways and found to agree (within experimental error) with the classic equation relating these three parameters. This gives us confidence that, for example, hot-spot ignition mechanisms of this class of energetic materials can be accurately modelled using their measured thermal properties. A modular instrumented testing facility has been designed and built to simulate and control the conditions experienced by novel heavy-metal-free (green) primers contained within ammunition. Physical data obtained from the facility, when compared with data from live fire tests, will give a greater understanding of which characteristics are important to functionality. As explosives are granular materials, the techniques developed for studying such materials are being applied to determine the effect of particle size distribution and shape on sensitivity.

9

Małowrażliwe materiały wybuchowe - 3-nitro-1,2,4-triazol-5-on

Powała D., Orzechowski A., Florczak B., Maranda A., Nowaczewski J.

Przemysł Chemiczny

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2006

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T. 85, nr 3

177-181

PL

Przedstawiono właściwości 3-nitro-1,2,4-triazol5-onu (NTO) oraz wyniki badań nad uzyskaniem jego odpowiedniej postaci krystalicznej. Przeprowadzono badania gęstości nasypowej i nasypowej utrzęsionej uzyskanych kryształów. Zbadano ich charakterystykę granulometryczną a także morfologię ziarna. Uzyskane kryształy wykorzystano do sporządzenia materiałów wybuchowych typu PBX (plastic bonded explosives). Przeprowadzono badania ich wrażliwości na bodźce mechaniczne.

EN

Semicarbazide hydrochloride reacted with aq. 85% HCOOH at 85–90°C to give TO which, with excess acid distd. off and reaction mixt. neutralized with aq.10% Na2CO3, was nitrated to yield NTO m. 267–9°C. This was recrystd. in 12.5 wt. parts of (9:1 v/v) EtOH–H2O, 2 hrs., 1000 rpm, at cooling rates of (i) 20 (ii) 3, and (iii) 10°C/min, to yield (i) spherical 50–150 µm polycrystals, bulk d. 0.77, and tap bulk d. 0.96; (ii) 50–350, 0.92, and 1.05; (iii) 50–300 µm, 0.81, and 1.01 g/ cm3, resp. NTO m.p., 267–8°C. Plastic-bonded explosives (PBX) were prepd., contg. 84 or 90% of 10–150 µm hexogen and NTO as additive, in a butadiene-styrene rubber as binder plastified with 16 or 10% of dioctyl adipate and oil. When added in 20, 20–60, and 80% to either the 84% or the 90% PBX, the NTO additive reduced, leveled off, and still more reduced the sensitivity of the PBX to impact, resp. The EtOH–H2O was superior to ethylene glycol as solvent. The properties of 3-nitro-1,2,4-triazol-5-one and investigations of this material in order to obtain suitable crystalline form were presented. The tests of bulk density and tap bulk density of obtained crystals were carried out. The grain size characteristic and grain morphology were investigated. The resulting crystals were used to prep. of Plastic Bonded Explosives. The tests of the PBX sensitivity to mechanical impacts were made.

10

Małowrażliwe materiały wybuchowe. Nitroguanidyna

Powała D., Orzechowski A., Maranda A., Nowaczewski J.

Przemysł Chemiczny

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2005

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T. 84, nr 8

582-585

PL

Przedstawiono właściwości nitroguanidyny oraz badania nad uzyskaniem jej postaci krystalicznej. Uzyskano sferyczne kryształy nitroguanidyny, zbadano ich gęstość nasypową i nasypową utrzęsioną, rozmiar ziaren oraz przedstawiono zdjęcia, ilustrujące strukturę otrzymanych kryształów. Sprawdzono przydatność tej formy krystalicznej jako dodatku do sporządzenia materiałów wybuchowych typu PBX (plastic bonded explosives). Stwierdzono, że dodatek nitroguanidyny do PBX powoduje obniżenie ich wrażliwości na bodźce mechaniczne.

EN

Authors’ prepd. NQ was dissolved in (1:22) glycol, (1:4) DMF, (1:2,5) DMSO, or (1:4 w/w) NMP and crystd. from supersatd. solns. at <50°C, cooling rate 3 or 10°C/min, at 800, 1000, 600, and 300 rpm by pptn. with Me2CO, –, EtOH, and Me2O, resp., to yield NQ of crystal size, bulk d. and tap bulk d. 80– 500 (plates), 0.25, 0.32; 100–400 (spherical polycrystals and needles), 0.58, 0.63; 70–600 (grains), 0.56, 0.60; and 80–300 µm (spherical polycrystals), 0.79 , 0.86 g/cm3, resp. The closest-packed (no needles) and densiest were the 30-ppm Ni(NO3)2-seeded, Me2CO-pptd. polycrystals from NMP. Plasticbonded explosives (PBX) were prepd., contg. 84% of (10– 150 µm hexogen + 80–300 µm NQ) and 16% of a butadiene-styrene rubber-based binder. With NQ added as flegmatizer in 20–80% to the 84% PBX, the sensitivity of the PBX fell so as to require impacts of 34.3–49.1 Nm (vs. the 29.4 for the 0%NQ PBX) to respond. The detonation velocity of the (15:80%) N-oktogen PBX, d. 1.775 g/cm3, was 8616 m/s.

11

Researches on New Crystalline Form of Some Insensitive High Explosives in PBX

Powała D., Orzechowski A., Maranda A., Nowaczewski J., Lorek A.

Central European Journal of Energetic Materials

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2004

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Vol. 1, nr 1

63-73

EN

In this paper, the results of researches on crystallization of insensitive high explosives were described. 3-Nitro-1,2,4-triazol-5-one (NTO) and nitroguanidine (NQ) were selected. The laboratory methods of preparation were presented. The influence of different solvents and other parameters on crystallization process was investigated. The results of the particle size distribution in the crystals obtained were presented. The suitability of NTO and NQ for their application in plastic bonded explosives (PBX) was checked.

12

Flexible plastic explosives with rubber NBR during artificial ageing

Chovancová M., Očko P., Lazar M., Lisý J., Lopúch J.

Problemy Techniki Uzbrojenia

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2003

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R. 32, z. 86

13--22

EN

This paper investigates chemical and thermal stability of flexible PBX's during their artificial ageing in term of their similar plastic binder. It was documented, they contain the rubber NBR and the similar base (RDX, PETN or RDX with PETN), but they don't have equivalent behaviour during the artificial ageing. It was discovered one from them is chemically unstable, because probably the rubber NBR is incompatible with RDX.

13

Wykorzystanie sieci telekomunikacyjnych do telepracy

Kozicki M.

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

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2002

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nr 11-12

690-697

PL

Przedstawiono podstawowe zagadnienia techniczne związane z problematyką telepracy. Opisane rozwiązania dotyczą środków łączności, jakie może zapewnić stacjonarny operator sieci publicznej przy realizacji usług dodanych. Przedstawiono alternatywne sposoby realizacji transmisji danych i łączności telefonicznej pomiędzy telepracownikami a biurem głównym przedsiębiorstwa.

EN

The article presents the main technical aspects connected with teleworking. The telecommunication solutions described concerns public fixed network operator who can realize value added service. The article presents alternative methods of data and voice services providing between teleworker and the main site of company.

14

Zastosowanie pyłu aluminiowego w wojskowych mieszaninach wybuchowych typu Plastic Bonded Explosives

Maranda A., Cudziło S., Ćwik R.

Problemy Techniki Uzbrojenia

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2000

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R. 29, z. 74

71--76

PL

W artykule przedstawiono przegląd danych literaturowych dotyczących zastosowania pyłu aluminiowego w materiałach wybuchowych typu Plastic Bonded Explosives. Przedstawiono również wyniki badań własnych wpływu dodatku dwóch typów pyłu aluminiowego na parametry Plastic Bonded Explosives opracowanego w Wojskowej Akademii Technicznej.