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Dinitro-diaza-alkanes (DNDA-57) are linear nitramine plasticizers and find use in low-temperature sensitivity coefficient propellants. DNDA-57 is a mixture of 2,4-dinitro-2,4-diazapentane (DNDA-5), 2,4-dinitro-2,4-diazahexane (DNDA-6), and 3,5-dinitro-3,5-diazaheptane (DNDA-7) with percentage composition of 40 ± 5%, 44 ± 5% and 11 ± 2%, respectively. The synthesis process of DNDA-57 was established with slight modification of the reaction parameters to obtain good yield and the process was scaled up. The synthesized compound was thoroughly characterized by spectroscopic as well as thermal methods. The present study emphasizes gas chromatographic–mass spectrometric (GC/MS) characterization by electron impact (EI) mode and chemical ionization (CI) mode to determine the fragmentation pattern. Further, the identified components were confirmed with general characterization. The study reveals that DNDA-5, DNDA-6, and DNDA-7 follow identical decomposition pattern. The friction and impact sensitivity study unveils the insensitive nature of DNDA-57. [ABSTRACT FROM AUTHOR]

An energetic plasticizer, 1,3-diazido-2-ethyl-2-nitropropane (DAENP), was synthesized and characterized in good yield and high purity. DAENP is synthesized in three steps: 1) 1-nitropropane is condensed with formaldehyde to yield 2-ethyl-2-nitro-1,3-propane diol; 2) 2-ethyl-2-nitro-1,3-propane diol on tosylation gave 2-ethyl-2-nitro-1,3-bis(p-toluene sulfonyl) propyl ester; 3) azidation of the tosylated compound gives DAENP. The product was characterized by elemental analysis, Fourier transform infrared (FTIR) spectroscopy and 1H-NMR and purity was tested by high-performance liquid chromatography (HPLC). Thermal studies revealed that DAENP is thermally stable up to 196°C, has high energy output of the order 2,056 J/g, and a very low glass transition temperature (−96.76°C). DAENP is compatible with energetic binders like glycidyl azide polymer (GAP), 3,3-bis (azido methyl)oxetane–tetra hydroxyl furan (BAMO-THF) copolymer, and poly-3-nitrato methyl-3-methyl oxtetane (poly NIMMO or PLN). Rheological and thermal data showed that it can be used successfully with these binders. [ABSTRACT FROM AUTHOR]

Different amino- and methyl-trinitrodiazoles have been considered as potential candidates for high explosives by quantum chemical treatment. Geometric and electronic structures, band gap, thermodynamic properties, crystal density, and detonation properties have been studied using density functional theory (DFT) at the B3LYP/aug-cc-pVDZ level. Presumably the relative positions of methyl or amino group and nitro groups in the trinitrodiazole determines the stability, sensitivity, and crystal density and thus detonation performance. The chemical energy of explosion (1.35 to 1.47 kcal/g), density (1.93 g/cm3), detonation velocity (9.0 to 9.30 km/s), and detonation pressure (38 to 40.10 GPa) of aminotrinitrodiazoles are comparable to 1,3,5-trinitro-1,3,5-triazinane (RDX) and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX). [ABSTRACT FROM AUTHOR]

Abstract: This paper explores the possibility of increasing the ballistic performance of gun propellant with the addition of inorganic additives viz. aluminium and ammonium perchlorate. Compositions based on propellant NQ containing additional aluminium and ammonium perchlorate in different parts were studied theoretically and experimentally. Performance in respect of ballistic parameters, sensitivity, thermal characteristics, thermal stability and mechanical properties are evaluated and compared with that of the conventional triple base propellant NQ. Experimental data on comparative study indicate that the compositions containing aluminium and ammonium perchlorate are superior to propellant NQ in respect of energy. [Copyright &y& Elsevier]

Potassium, rubidium, and cesium salts of 5,7-diamino- 4,6-dinitrobenzofuroxan (CL-14) have been prepared by reacting sodium salt of 5,7-diamino-4,6-dinitrobenzofuroxan with alkali metal nitrate in an aqueous medium. The structure of the compounds was unequivocally confirmed by spectra data, elemental analyses, and estimation of metal content. Further, the compounds have been evaluated for explosive and thermal properties and found more suitable as compared to alkali metal salts of 4,6-dinitrobenzofuroxan (DNBF). [ABSTRACT FROM AUTHOR]

Diamond films with dominant (100) texture were grown with a temperature gradient across the Si (100) substrates using hot filament chemical vapor deposition technique. Deposition was carried out with 0.8% CH4 in balance hydrogen at an average substrate temperature of 880 °C. The deposition pressure was varied between 20–120 torr. Films were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). XRD shows very strong (400) reflection in all the samples. SEM results show a smooth diamond surface comprised of (100) platelets. As the (100) diamond plates were grown on top of the (100) oriented silicon substrate the faces are more or less aligned parallel with the substrate surface, resulting in a relatively smoother diamond surfaces. FTIR studies show novel features in the films. Quantitative analysis was carried out to measure the H content in the films. [Copyright &y& Elsevier]

Abstract: In this investigation, diamond sheets have been deposited using chemical vapor deposition. The as-grown diamond sheets were characterized for hydrogen content using detailed infrared analysis. The deconvolution of the spectra in the three-phonon region (2700–3150 cm−1) showed a number of vibration modes corresponding to sp m CH n phase of carbon. The spectra representing (100) and (111) textured diamond sheets, grown under different conditions, was compared. The (100) textured sheets contained two dominant peaks centred at 2860 cm−1 and 2930 cm−1, which correspond to the symmetric and asymmetric stretch bands of CH2 group. However, the sheet with (111) texture displayed multiple CH, CH2 and CH3 peaks on the spectra. Using a standard sample called polymethyl methacrylate with known concentration, H content associated with various modes was evaluated in the diamond sheets. IR active hydrogen in the CVD diamond sheets was also calculated by evaluating the area of the IR band. Using these measurements we suggest that the oscillator strength of the different IR modes varies depending upon the structure and H content of CVD diamond sheets. [Copyright &y& Elsevier]

3-Nitro-1,2,4-triazol-5-one (NTO) is a promising candidate of insensitive munitions and it is currently explored to achieve shock insensitive melt-cast formulations. Rheology of melt-cast formulations helps in implementing viscous behaviour to application. In the present study, NTO based melt-cast formulations are prepared using TNT as a dispersant and the flow behaviour of non-spherical and spherical NTO formulations are studied along with the bench-mark Composition B. All measurements are made at 81, 83, 86 and 90 °C and at shear rates varying from 8.5 to 59.5 s − 1 . Flow behaviour of these formulations at process temperatures exhibit non-Newtonian behaviour with yield stress. Time and temperature dependency of these formulations are also studied and about two fold increase in thixotropic index is observed in RDX/TNT in comparison to spherical NTO/TNT (60:40). In order to get more insight on the flow properties, molecular–orbital calculations were performed at B3LYP 6-311G (d, p) level. The calculated interaction energies revealed that stronger attractive forces exist in NTO–NTO than RDX–RDX pairs and similarly in NTO–TNT than RDX–TNT. Correlation with particle morphology confirms domination of morphology over intra/intermolecular interactive forces in determining the yield value. This comparative study establishes the role of above interactive forces and morphology on pourability of melt-cast formulations and further reveals that the flow behaviour of NTO based formulations is superior to RDX/TNT formulations. [ABSTRACT FROM AUTHOR]

Abstract: Particles with spherical shape and specific size distribution are major considerations in achieving high performance, solid loading and mix fluidity in processing of energetic materials for high explosive/rocket propellant applications. Spherical 3-Nitro-1, 2, 4-triazol-5-one (NTO) of specific particle size distribution (PSD) was prepared by a proprietary process and the powders were characterized by X-ray powder diffraction, thermal and spectral methods. Present study explores the spherical-NTO of specific particle size D (4, 3) of 150, 100, 25, 15, 10, and less than 5μm and their bi/trimodal mixtures for their micromeritic properties. From the packability and flowability constants, bimodal mixture of coarse (150μm) to fine (25μm) ratio of 70:30 is found to be optimum for processing in explosive formulations. Paste explosive formulations were made based on identified bimodal mixture and their flow behavior studied by viscosity studies. The study inferred that spherical particles of NTO bring down the viscosity by about 75% for the same explosive content to binder ratio in comparison with non-spherical-NTO. Porosity data also supports the same for improvement in explosive loading by 10% by the usage of spherical-NTO over non-spherical particles for the given explosive to binder ratio. [Copyright &y& Elsevier]

Abstract: Density functional theory (DFT) calculations at the B3LYP/aug-cc-pVDZ level have been performed on the condensed polynitroazoles based on diazole and triazole skeletons. Energy of explosion (≈1.60kcal/g), density (≈1.92g/cm3), detonation velocity (≈9.30km/s), and detonation pressure (≈ 39GPa) of model molecules are found to be promising compared to the well known explosives 1,3,5-trinitro-1,3,5-triazinane (RDX), octahydro-1,3,5,7-tetranitro-l,3,5,7-tetraazocane (HMX), and 4,4′,5,5′-tetranitro-2,2′-bi-1H-imidazole (TNBI). Presumably, the relative positions of nitro groups and the nature of azole ring determines the geometry, stability, sensitivity, density and thus detonation performance. [Copyright &y& Elsevier]

Abstract: In this study, fused nitroazoles based on imidazole, pyrazole, and triazole skeletons have been considered as potential candidates for high explosives by quantum chemical treatment. Geometric and electronic structures, band gap, thermodynamic properties, crystal density, and detonation properties have been studied using density functional theory (DFT) at the B3LYP/aug-cc-pVDZ level. The chemical energy of explosion (≈ 1.70kcal/g), density (≈ 1.93g/cm3), detonation velocity (≈ 9.30km/s), and detonation pressure (≈ 40.00GPa) of designed compounds are found to be superior to octahydro-1,3,5,7-tetranitro-l,3,5,7-tetraazacyclooctane (HMX), 3,6-dinitropyrazolo[4,3-c]pyrazole (DNPP), and 1,4-diamino-3,6-dinitropyrazolo[4,3-c]pyrazole (LLM-119). Presumably the relative positions of nitro groups determines the stability, sensitivity, and crystal density thus detonation performance. [Copyright &y& Elsevier]

Abstract: This paper briefly reviews the literature work reported on the environmentally compatible green energetic materials (GEMs) for defence and space applications. Currently, great emphasis is laid in the field of high-energy materials (HEMs) to increase the environmental stewardship along with the deliverance of improved performance. This emphasis is especially strong in the areas of energetic materials, weapon development, processing, and disposal operations. Therefore, efforts are on to develop energetic materials systems under the broad concept of green energetic materials (GEMs) in different schools all over the globe. The GEMs program initiated globally by different schools addresses these challenges and establishes the framework for advances in energetic materials processing and production that promote compliance with environmental regulations. This review also briefs the principles of green chemistry pertaining to HEMs, followed by the work carried out globally on environmentally compatible green energetic materials and allied ingredients. [Copyright &y& Elsevier]

Abstract: The thermal decomposition study of CL-20 (hexanitrohexaazaisowurtzitane) using pyrolysis GC/MS was carried out mainly by electron impact (EI) mode. Chemical ionization (CI) mode was used for further confirmation of identified species. Mass spectrum of CL-20 decomposition products predominantly revealed fragments with m/z 81 and 96 corresponding to C4H5N2 + and C4H4N2O+ ions, respectively. The total ion chromatogram (TIC) of CL-20 pyrolysis shows peak within first 2min due to the presence of low molecular weight gases. Peaks corresponding to several other products were also observed including the atmospheric gases. Cyanogen formation (C2N2, m/z 52) observed to be enriched at the scan number 300–500. The low molecular mass range decomposition products formed by cleavage of C–N ring structure were found in majority. Additional structural information was sought by employing chemical ionization mode. The data generated during this study was instrumented in determining decomposition pathways of CL-20. [Copyright &y& Elsevier]