Surfactant Assisted Self-assembly and Synthesis of Highly Uniform Spherical CL-20 Microparticles

MRS Advances ◽  
2018 ◽  
Vol 3 (41) ◽  
pp. 2421-2427 ◽  
Author(s):  
Kaifu Bian ◽  
Leanne Alarid ◽  
David Rosenberg ◽  
Hongyou Fan
Keyword(s):  
Self Assembly ◽  
Energetic Materials ◽  
Energetic Material ◽  
Critical Role ◽  
X Ray Diffraction ◽  
Β Phase ◽  
Micron Particle ◽  
The Subject ◽  
Detailed Electron Microscopy ◽  
Surfactant Assisted

ABSTRACTMorphological control of energetic materials (EM) is highly desired because ill-defined morphology arising from variations in processing method and supplier make it impossible to reproducibly engineer their physicochemical properties. As the most powerful, non nuclear energetic material to date, 2,4,6,8,10,12-hexanitro -2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) has been the subject of significant interest for improved applications in military grade explosives. Here we report a new method for recrystallization of CL-20 from irregular bulk EMs using a surfactant assisted self-assembly process to produce uniform spherical micron-sized particles. Detailed electron microscopy studies indicate that surfactant plays a critical role in controlling CL-20 morphology. Combined X-ray diffraction and Raman spectroscopy results reveal that the resultant spherical CL-20 particles exhibit an orthorhombic β-phase crystal structure. This material is expected to display enhanced functional reproducibility due to its monodisperse nature as well as decreased shock sensitivity due to their sub-micron particle size.

Preparation of Carbon Micro-Spheres from Liquefaction Products of Lignite with NaOH-Methanol

2012 ◽  
Vol 560-561 ◽  
pp. 267-270
Author(s):  
Zhi Ping Lei ◽  
Li Juan Gao ◽  
Heng Fu Shui ◽  
Zhi Cai Wang ◽  
Shi Biao Ren
Keyword(s):  
Self Assembly ◽  
Cetyltrimethylammonium Bromide ◽  
Reaction System ◽  
X Ray Diffraction ◽  
X Ray ◽  
N2 Atmosphere ◽  
High Thermal Resistance ◽  
Direct Coal Liquefaction ◽  
Coal Liquefaction Products ◽  
Surfactant Assisted

Carbon micro-spheres (CMSs) with diameters of several micrometers were synthesized by surfactant-assisted self-assembly of direct coal liquefaction products, which come from the lignite liquefaction with NaOH and methanol. The synthesized CMSs were characterized by X-ray diffraction, scanning electron microscope and TG analysis. The results show that cetyltrimethylammonium bromide (CTAB) and carbonization temperature play an important role in the formation of CMSs. The CMSs have a spherical morphology, smooth surface, probable size of about 5-10μm and a relatively high thermal resistance in N2 atmosphere. The formation mechanism of these CMSs was discussed based on the feature of the reaction system.

Structure and properties of Al–Mg mechanical alloys

2003 ◽  
Vol 18 (8) ◽  
pp. 1827-1836 ◽  
Author(s):  
Mirko Schoenitz ◽  
Edward L. Dreizin
Keyword(s):  
Solid Solution ◽  
Energetic Materials ◽  
Amorphous Material ◽  
Bulk Composition ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Β Phase ◽  
Α Phase ◽  
Diffraction Microscopy

Mechanically alloys in the Al–Mg binary system in the range of 5–50 at.% Mg were produced for prospective use as metallic additives for propellants and explosives. Structure and composition of the alloys were characterized by x-ray diffraction microscopy (XRD) and scanning electron microscopy. The mechanical alloys consisted of a supersaturated solid solution of Mg in the α aluminum phase, γ phase (Al12Mg17), and additional amorphous material. The strongest supersaturation of Mg in the α phase (20.8%) was observed for bulk Mg concentrations up to 40%. At 30% Mg, the γ phase formed in quantities detectable by XRD; it became the dominating phase for higher Mg concentrations. No β phase (Al3Mg2) was detected in the mechanical alloys. The observed Al solid solution generally had a lower Mg concentration than the bulk composition. Thermal stability and structural transitions were investigated by differential scanning calorimetry. Several exothermic transitions, attributed to the crystallization of β and γ phases were observed. The present work provides the experimental basis for the development of detailed combustion and ignition models for these novel energetic materials.

scholarly journals Explosives at Extreme Conditions: Polymorphism of 2,4-Dinitroanisole

2014 ◽  
Vol 70 (a1) ◽  
pp. C896-C896 ◽  
Author(s):  
Paul Coster ◽  
Craig Henderson ◽  
Steven Hunter ◽  
William Marshall ◽  
Colin Pulham
Keyword(s):  
High Pressure ◽  
Energetic Materials ◽  
Variable Temperature ◽  
Energetic Material ◽  
X Ray Diffraction ◽  
Temperature And Pressure ◽  
First Time ◽  
Pressure Phase ◽  
Kinetic Form

2,4-dinitroanisole (DNAN) is an energetic material, developed as an insensitive replacement for TNT in melt-cast explosive formulations. While DNAN-based formulations demonstrate greatly reduced sensitivity to accidental initiation compared to those using TNT, issues remain with the replacement of TNT with DNAN. For instance, DNAN based formulations have demonstrated catastrophic levels of irreversible growth during heat-cycling, with volume increases of up to 15% reported. [1] In order to investigate the role of polymorphism in the irreversible growth of DNAN, high-pressure and variable-temperature neutron and x-ray diffraction studies have been performed. Two polymorphs of DNAN have been found to exist at ambient temperature and pressure, the thermodynamic form, DNAN-I, and the kinetic form, DNAN-II.[2,3] The phase diagrams of both form-I and -II of DNAN have been explored for the first time. In the case of DNAN-II, two high-pressure phase transitions were found. DNAN-II initially transformed to DNAN-III, which at higher pressures transformed to DNAN-IV. In addition, variable temperature studies demonstrated that the DNAN-II to DNAN-III transition also occurs when DNAN-II is cooled below room temperature. The thermal expansion of the DNAN-II/III lattice was investigated from 150K to 363K, demonstrating that an abrupt change in the thermal behaviour of lattice parameters occurs at the DNAN-II/III transition. From these combined crystallographic studies, the structure of DNAN-III has been solved, showing it is closely related to DNAN-II. In the case of DNAN-I, high-pressure neutron powder diffraction studies demonstrated that it transforms to a new form (DNAN-V) that is distinct from DNAN-II,-III or -IV. Rietveld refinement of the high-pressure DNAN-I data also determined that the material exhibits negative linear compressibility, which is of interest given the use of DNAN as a shock-insensitive energetic material. Comparison of the behaviour of DNAN-I and –II under variable temperature and high-pressure conditions indicates that the kinetic form, DNAN-II, is the denser phase under all conditions studied. This work highlights the importance of crystallographic techniques in order to understand the polymorphism of energetic materials.

Enhancing chemical stability of tetranitro biimidazole-based energetic materials through co-crystallization

2020 ◽  
Vol 98 (7) ◽  
pp. 358-364
Author(s):  
Manomi D. Perera ◽  
Abhijeet S. Sinha ◽  
Christer B. Aakeröy
Keyword(s):  
Hydrogen Bond ◽  
Energetic Materials ◽  
Energetic Material ◽  
Parent Compound ◽  
Site Formation ◽  
Acceptor Site ◽  
Oxygen Balance ◽  
X Ray Diffraction ◽  
Hydrogen Bond Acceptor ◽  
X Ray

Co-crystallization technology was employed as a way of solving two problems hampering the usefulness of 4,4′,5,5′-tetranitro-2,2′biimidazole (TNBI) as a viable energetic material, namely hygroscopicity and corrosiveness (high acidity). Co-crystal screening was carried out with 15 co-formers containing nitrogen or oxygen as the primary hydrogen-bond acceptor site. Formation of co-crystals was confirmed by IR spectroscopy and DSC, and suitable co-crystals were then analysed via single-crystal X-ray diffraction. In each case, the formation of a co-crystal was driven by the formation of multiple N–H···N or N–H···O hydrogen bonds between TNBI and the co-former. The N-oxide based acceptors produce better energetic materials due to a more optimal oxygen balance. Hygroscopicity evaluations and corrosion tests revealed that the unavailability of N–H protons in the co-crystals of TNBI reduce hygroscopicity and suppress the chemical acidity of the free parent compound thereby making it substantially easier to handle, store, and transport.

A polyoxometalate-based metal–organic polyhedron constructed from a {V5O9Cl} building unit with rhombicuboctahedral geometry

2018 ◽  
Vol 74 (11) ◽  
pp. 1243-1247 ◽  
Author(s):  
Ya-Ru Gong ◽  
Zhong-Min Su ◽  
Xin-Long Wang
Keyword(s):  
Self Assembly ◽  
Title Compound ◽  
Outer Diameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Building Unit ◽  
Secondary Building Units ◽  
Metal Organic ◽  
The Subject ◽  
Solvothermal Conditions

The design and construction of metal–organic polyhedra has received much attention by chemists due to the intriguing diversity of architectures and topologies that can be achieved. There are several crucial factors which should be considered for the construction of metal–organic polyhedra, such as the starting materials, reaction time and temperature, solvent and suitable organic ligands. Recently, polyoxometalates (POMs), serving as secondary building units to construct POM-based metal–organic polyhedra, have been the subject of much interest. The title compound, dodecakis(dimethylammonium) octakis(μ-benzene-1,3,5-tricarboxylato)hexa-μ-chlorido-tetracosa-μ-oxido-triacontaoxidotriacontavanadium, (NH2Me2)12[(V5O9Cl)6(C9H3O6)8], was synthesized successfully by self-assembly of VOCl3 and benzene-1,3,5-tricarboxylic acid under solvothermal conditions. The title polyhedron has an rdo topology when the {V5O9Cl} building unit and the benzene-1,3,5-tricarboxylate (BTC3−) ligand were simplified into 4-connected and 3-connected vertices. Interestingly, when the {V5O9Cl} building unit and the BTC3− ligand are considered as quadrangular and triangular faces, the structure displays rhombicuboctahedral geometry with an outer diameter of 21.88 Å. The packing of the polyhedra produces a circular channel with a diameter of 8.2 Å. The title compound was characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, thermogravimetric analysis and powder X-ray diffraction.

Chemical bonding and intermolecular interactions in energetic materials: 1,3,4-trinitro-7,8-diazapentalene

2007 ◽  
Vol 63 (2) ◽  
pp. 309-318 ◽  
Author(s):  
Yu-Sheng Chen ◽  
Adam I. Stash ◽  
A. Alan Pinkerton
Keyword(s):  
Electron Density ◽  
Intermolecular Interactions ◽  
Single Molecule ◽  
Critical Points ◽  
Energetic Materials ◽  
Theoretical Calculations ◽  
Energetic Material ◽  
X Ray Diffraction ◽  
Multiple Bonds ◽  
Acta Cryst

The electron density and related properties of the red-colored energetic material 1,3,4-trinitro-7,8-diazapentalene (space group Pca21) have been determined from a low-temperature [90.0 (1) K] X-ray diffraction experiment. Intensity data were measured with a 2 K CCD Bruker diffractometer using Ag Kα radiation. One detector setting, several φ settings, 0.15° ω scans and 96 s exposure time per frame gave R int = 0.0188 for 31 952 (10 283 unique) reflections and (sin θ/λ)max = 1.15 Å−1. The electron density was modeled using the Hansen–Coppens [(1978), Acta Cryst. A34, 909–921] multipole model and refined to R = 0.026 for 9455 unique observed reflections. The electron density, Laplacian and electrostatic potential distributions are reported and discussed. The properties of the bond (3,−1) critical points are analyzed. All results are indicative of multiple bonds in the five-membered rings. In addition, a significant number of weak intermolecular interactions (O...H, O...O, O...N, O...C) have also been characterized by the properties of their critical points. A comparison of experimental results with those obtained from theoretical calculations (periodic, CRYSTAL98; single molecule, GAUSSIAN98) is also reported.

Self-Assembly Optical Components

2003 ◽  
Vol 771 ◽  
Author(s):  
Pavel I. Lazarev ◽  
Michael V. Paukshto ◽  
Elena N. Sidorenko
Keyword(s):  
Optical Properties ◽  
Self Assembly ◽  
Crystalline State ◽  
Liquid Crystalline ◽  
Film Deposition ◽  
X Ray Diffraction ◽  
Optical Components ◽  
Crystal Film ◽  
Solid Film ◽  
Thin Crystal

AbstractWe report a new method of Thin Crystal Film deposition. In the present paper we describe the method of crystallization, structure, and optical properties of Bisbenzimidazo[2,1-a:1',2',b']anthra[2,1,9-def:6,5,10-d'e'f']-diisoquinoline-6,9-dion (mixture with cis-isomer) (abbreviated DBI PTCA) sulfonation product. The Thin Crystal Film has a thickness of 200-1000 nm, with anisotropic optical properties such as refraction and absorption indices. X-ray diffraction data evidences a lyotropic liquid crystalline state in liquid phase and crystalline state in solid film. Anisotropic optical properties of the film make it useful in optical devices, e.g. liquid crystal displays.

Mechanical Alloying Behavior in the Nb-Si, Ta-Si, and Nb-Ta-Si Systems

1988 ◽  
Vol 133 ◽  
Author(s):  
K. S. Kumar ◽  
S. K. Mannan
Keyword(s):  
High Temperature ◽  
Mechanical Alloying ◽  
Mechanical Milling ◽  
Room Temperature ◽  
Crystalline Compound ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Α Phase

ABSTRACTThe mechanical alloying behavior of elemental powders in the Nb-Si, Ta-Si, and Nb-Ta-Si systems was examined via X-ray diffraction. The line compounds NbSi2 and TaSi2 form as crystalline compounds rather than amorphous products, but Nb5Si3 and Ta5Si3, although chemically analogous, respond very differently to mechanical milling. The Ta5Si3 composition goes directly from elemental powders to an amorphous product, whereas Nb5Si3 forms as a crystalline compound. The Nb5Si3 compound consists of both the tetragonal room-temperature α phase (c/a = 1.8) and the tetragonal high-temperature β phase (c/a = 0.5). Substituting increasing amounts of Ta for Nb in Nb5Si3 initially stabilizes the α-Nb5Si3 structure preferentially, and subsequently inhibits the formation of a crystalline compound.

Introduction of the acylamino group to bridged bis(nitroamino-1,2,4-triazole): a strategy for tuning the sensitivity of energetic materials

2021 ◽  
Vol 45 (38) ◽  
pp. 18059-18064
Author(s):  
Dongxu Chen ◽  
Jiangshan Zhao ◽  
Hongwei Yang ◽  
Hao Gu ◽  
Guangbin Cheng
Keyword(s):  
Energetic Materials ◽  
Energetic Material

Introduction of the acylamino group into energetic material compounds will contribute to balancing the sensitivity and the energy.

scholarly journals Taming nitroformate through encapsulation with nitrogen-rich hydrogen-bonded organic frameworks

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jichuan Zhang ◽  
Yongan Feng ◽  
Richard J. Staples ◽  
Jiaheng Zhang ◽  
Jean’ne M. Shreeve
Keyword(s):  
Thermal Stability ◽  
Hydrogen Bonds ◽  
Self Assembly ◽  
Energetic Materials ◽  
Decomposition Temperature ◽  
High Oxygen Content ◽  
The Poor ◽  
Simple Preparation ◽  
First Time ◽  
Hydrogen Bonded

AbstractOwing to its simple preparation and high oxygen content, nitroformate [−C(NO2)3, NF] is an extremely attractive oxidant component for propellants and explosives. However, the poor thermostability of NF-based derivatives has been an unconquerable barrier for more than 150 years, thus hindering its application. In this study, the first example of a nitrogen-rich hydrogen-bonded organic framework (HOF-NF) is designed and constructed through self-assembly in energetic materials, in which NF anions are trapped in pores of the resulting framework via the dual force of ionic and hydrogen bonds from the strengthened framework. These factors lead to the decomposition temperature of the resulting HOF-NF moiety being 200 °C, which exceeds the challenge of thermal stability over 180 °C for the first time among NF-based compounds. A large number of NF-based compounds with high stabilities and excellent properties can be designed and synthesized on the basis of this work.

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