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Wyszukujesz frazę "CL-20" wg kryterium: Temat


Tytuł:
Quantitative analysis of α-CL-20 polymorphic impurity in ε-CL-20 using Dispersive Raman Spectroscopy
Autorzy:
Ghosh, M.
Venkatesan, V.
Sikder, N.
Sikder, A. K.
Tematy:
CL-20
polymorphs
α-CL-20 impurity
Dispersive Raman Spectroscopy
Pokaż więcej
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:
https://bibliotekanauki.pl/articles/951498.pdf  Link otwiera się w nowym oknie
Opis:
α-CL-20 polymorphic impurity in ε-CL-20 studies have been carried out using Dispersive Raman Spectroscopy. ε-, β-, α- and γ-CL-20 polymorphs were produced using crystallization methods with sample recovery from the solution being >90%, and chemical purity of about 99%. The polymorphs prepared were characterized using Dispersive Raman Spectroscopy over the Raman shift region of 100-3500 cm-1 using a 514 nm argon ion laser. The experimental studies were supported by ab initio computations performed at B3LYP level using a 6-31+G** basis set. The computed vibrational frequencies of the CL-20 conformers correspond to the ε, β and α or γ-CL-20 polymorphs when compared with the observed frequencies. α-CL-20 shows a distinct feature at 280 cm-1 as compared with those of the ε-CL-20 polymorph. Using Dispersive Raman Spectroscopy, a linear relationship was demonstrated for the absolute peak height and absolute peak area ratio of α-CL-20 versus the weight percent of α-CL-20. This method enables a detection limit of this polymorphic impurity down to 2 wt%.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation and Characterization of CL-20 Based Composites by Compressed Air Spray Evaporation
Autorzy:
Xu, Wen Zheng
Peng, Jin Yu
Wang, Jie
Li, Hao
Wang, Jing Yu
Tematy:
CL-20
CL-20-based composites
thermal stability
mechanical sensitivity
Pokaż więcej
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:
https://bibliotekanauki.pl/articles/358401.pdf  Link otwiera się w nowym oknie
Opis:
Ultrafine CL-20 particles and three CL-20-based composites were prepared by a compressed air spray evaporation method. All samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and mechanical sensitivity instruments. The results indicated that the thermal stabilities of the CL-20-based composites are better than that of ultrafine CL-20, and that the mechanical sensitivities of ultrafine CL-20 is lower than those of CL-20-based composites. The thermal stability and safety properties of CL-20/Estane 5703 are better than the other samples.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metody syntezy i właściwości fizykochemiczne 2,4,6,8,10,12-heksanitro-2,4,6,8,10,12-heksaazaizowurcytanu (HNIW)
The methods of synthesis and physicochemical properties of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (HNIW)
Autorzy:
Borkowski, J.
Czerwińska, M.
Tematy:
Cl-20
HNIW
synteza
właściwości chemiczne
właściwości wybuchowe
CL-20
synthesis
chemical properties
explosive properties
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Wydawca:
Polskie Towarzystwo Chemiczne
Powiązania:
https://bibliotekanauki.pl/articles/171958.pdf  Link otwiera się w nowym oknie
Opis:
Explosives have a very rich history of its creation. This history dates back to the ninth century, when the Chinese invented a black powder. In the end of the twentieth century, the first nitroamine polycyclic cage structure was obtained. The representative of this group is 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaizowurtzitane (HNIW, Cl-20). HNIW has recently been the subject of an interest as one of the strongest explosive material. As nitroamine, HNIW is compared to the other energetic materials: RDX i HMX [1, 2]. Researchers [5, 6] showed, that it is possible to replace a variety of typical explosives by HNIW and thanks to that obtain compositions with higher densities, heat of explosion and higher velocity of detonation. In the published papers [7-13, 16] there were presented six polymorphs of HNIW: αβγδε with specific stabilities and structural characteristics. Unfortunately, there is no a direct method of obtaining HNIW. There are at least four steps needed to obtain HNIW. The first step is the synthesis of HBIW [20-22]. The next one is debenzylation reaction of HBIW [20-29] in order to remove the benzyl groups. The third step is removal of the two other benzyl groups and replace them by nitroso, formyl or acetyl groups [20, 24, 30, 32]. In the final step there is a nitration of HNIW precursors [31-37]. The HNIW seems to be a promising explosive and it can replace other currently used energetic materials. However, using HNIW is limited due to the complicated and expensive technology of its production. Therefore, research groups carried out new syntheses of HNIW to eliminated these problem. In this article, review of the literature on the physicochemical properties and synthetic methods for HNIW were presented. The basic physical and explosive parameters of HNIW were summarized. The spatial structure was presented and polymorphs of HNIW were characterized. The methods for obtaining HNIW and intermediate products needed for its preparation were described. The methods of preparation of different HNIW polymorphs were also given.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of the Effect of DINA on the Polymorphic Transition of ε-CL-20 in Composite Modified Double Base Propellants
Autorzy:
Wu, Zongkai
Zheng, Wei
Pei, Jiangfeng
Chen, Zhiqun
Zhang, Jun
Song, Xiuduo
Wang, Jiangning
Zhang, Dongxiang
Zhao, Fengqi
Tematy:
CMDB propellant
CL-20
DINA
polymorphic transition
Pokaż więcej
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:
https://bibliotekanauki.pl/articles/27788019.pdf  Link otwiera się w nowym oknie
Opis:
Abstract: The polymorphic transition of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.05,9.03,11]dodecane (CL-20) is influenced by the materials and conditions used in the preparation of propellants, and limits the application of ε-CL-20 in solid propellants. In the present work, the effect of dinitroxydiethylnitramine (DINA) on the polymorphic transition of ε-CL-20 in CMDB propellants was investigated by Raman spectroscopy and the Calvet microcalorimeter method. The performance of propellants with CL-20 as affected by DINA was studied by the theoretical prediction of their energetic parameters, stability, combustion, and mechanical tests, respectively. The results showed that the polymorphic transition temperature of ε-CL-20 to α-CL-20 can be reduced to 75 °C by DINA. Expansion of the crystal volume during the process of the ε-CL-20 to α-CL-20 transition will produce obvious cracks in the surface of the crystals. NC/NG can inhibit the effect of DINA on the polymorphic transition of ε-CL-20. The theoretically predicted results indicated that adding DINA will not lower the energy level of CMDB propellants containing CL-20. The DSC and VST results showed that CL-20 has good compatibility and thermal stability with DINA. The burning rate tests revealed that adding DINA decreases the burning rates of CMDB propellants containing CL-20. Mechanical property testing showed that adding DINA can clearly improve the mechanical properties of CMDB propellants containing CL-20. The results of these investigations suggested that DINA has no effect on the crystalline stability of ε-CL-20 in the solventless extrusion process, which contributes to a significant understanding of practical applications and provides guidance for applied research on the use of CL-20 in propellants.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermally induced damage in hexanitrohexaazaisowurtzitane
Autorzy:
Tian, Q.
Yan, G.
Sun, G.
Huang, C.
Xie, L.
Chen, B.
Huang, M.
Li, H.
Liu, X.
Wang, J.
Tematy:
CL-20
SAXS
AFM
thermal effects
voids
Pokaż więcej
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:
https://bibliotekanauki.pl/articles/358735.pdf  Link otwiera się w nowym oknie
Opis:
The evolution of the microstructure of hexanitrohexaazaisowurtzitane (CL-20) after a thermal stimulus plays a key role in the performance of CL-20. In the current work, microstructural variations of CL-20 caused by thermal treatment were investigated by X-ray diffraction, in situ variable-temperature optical microscopy, atom force microscopy, and small-angle X-ray scattering. A wave-like process, an abrupt volume expansion, movement, and fragmentation of CL-20 particles during phase transition were observed. After the phase transition (160 °C) the CL-20 sample acquired a very rough surface with numerous dimple depressions, and during the thermal decomposition stage (200 °C) a large number of voids were produced in both the bulk and the surface of the CL-20.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties of the Gamma-Cyclodextrin/CL-20 System
Autorzy:
Maksimowski, P.
Rumianowski, T.
Tematy:
CL-20/γ-CD complex preparation
properties of CL-20/γ-CD complex
cyclodextrin
2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane
CL-20
Pokaż więcej
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:
https://bibliotekanauki.pl/articles/358219.pdf  Link otwiera się w nowym oknie
Opis:
Cyclodextrin (CD) is a cyclic compound with a spatial structure in the shape of a toroid. It is characterized by specific properties. The outer portion of the structure has hydrophilic properties, while the cavity of the toroid is hydrophobic. This enables cyclodextrin to form inclusion complexes with the enclosure of lipophilic molecules in the interior. This paper presents the results of attempts to form a complex of γ-CD/CL-20. This study determined unambiguously that a γ-CD with CL-20 complex in a mole ratio 1:1 is formed as a result of mixing of solutions of γ-CD and CL-20. This conclusion was corroborated by FTIR, 1H NMR, UV-Vis spectroscopic techniques and by measurement of the density of the complex obtained. The resulting complex of γ-CD/CL-20 is characterized by much lower sensitivity to friction and impact than CL-20 itself.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication of Nano- and Micron- Sized Spheres of CL-20 by Electrospray
Autorzy:
Yan, S.
Li, M.
Sun, L.
Jiao, Q.
Huang, R.
Tematy:
energetic materials
explosives
CL-20
electrospray
spherical particles
Pokaż więcej
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:
https://bibliotekanauki.pl/articles/358652.pdf  Link otwiera się w nowym oknie
Opis:
The application of hexanitrohexaazaisowurtzitane (CL-20) in energetic materials will be expanded by its use as superfine particles. A method of fabricating nano- and micron-sized spheres of CL-20 by using electrospray is discussed. The effects of the precursor solution and the experimental conditions on the morphology and the crystal phase of the CL-20 particles are introduced. A variety of solvents was used to dissolve raw CL-20 for the preparation of the precursor solution with different CL-20 contents. The conductivity and viscosity of the precursor solutions were tested before the electrospray process. The electrostatic parameters were adjusted by changing the voltage and the distance between the nozzle and the plate. The morphology, crystal phase, mechanical sensitivity, density, and thermal stability of the raw CL-20 and the as-sprayed CL-20 samples were determined using scanning electron microscopy, X-ray diffraction, and differential scanning calorimetry (DSC). Furthermore, the density and the mechanical sensitivity were tested for the raw and the as-sprayed CL-20. DSC tests were conducted to compare the thermal stability and reactivity of the samples.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation of MCM-41 Supported Benzene Sulphonic Acid, a Catalyst for the Synthesis of CL-20 from TAIW
Autorzy:
Chen, Shixiong
Yang, Chaofei
Qian, Hua
Liu, Dabin
Kai, Wang
Li, Rui
Tematy:
CL-20
catalytic
MCM-41
benzene sulphonic acid
TAIW
Pokaż więcej
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:
https://bibliotekanauki.pl/articles/358326.pdf  Link otwiera się w nowym oknie
Opis:
Pure MCM-41 anchored benzene sulphonic acid (BSA/MCM-41), an efficient heterogeneous catalyst, was prepared for the synthesis of CL-20 from TAIW. The prepared catalysts were fully characterized by FTIR, XRD, TEM, TG, N2 adsorption techniques, elemental analysis and acidity tests. It was observed that the catalyst (BSA/MCM-41) retained the mesoporous structure like MCM-41, exhibited excellent thermal stability and high activity. Compared with a blank, the high catalytic activity promoted shorter reaction times by a factor of 3/5. In addition, this catalyst could be reused at least five times without significant loss of its catalytic potential. Moreover, the BSA/MCM-41 catalyst exhibited an optimal catalytic performance, with a high to excellent yield of CL-20 (92.5%) with a purity of 98.3%, under the optimum synthesis conditions.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation and Characterization of CL-20/EPDM by a Crystal Refinement and Spray Drying Method
Autorzy:
Ji, W.
Li, X.
Wang, J.
Tematy:
CL-20/EPDM
spray drying
impact sensitivity
thermal stability
Pokaż więcej
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:
https://bibliotekanauki.pl/articles/358349.pdf  Link otwiera się w nowym oknie
Opis:
A 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) based mixed explosive was prepared by a spray drying method using CL-20 suspended in hexane containing EPDM rubber (ethylene-propylene-diene monomer), and made into a stable suspension. The samples were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), and their thermal stability and impact sensitivity were also measured. The results showed that the ethylene-propylene-diene-monomer rubber (EPDM) can be successfully coated on to the CL-20 crystal surface. Compared to refinement-spray CL-20, the impact sensitivity of CL-20/EPDM was significantly reduced. The characteristic drop height was increased from 28.12 to 39.78 cm. The thermal stability was better than refinement-spray CL-20.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Purification of Hexabenzylhexaazaisowurtzitane
Autorzy:
Gołofit, T.
Maksimowski, P.
Tematy:
HBIW
CL-20
purification
differential scanning calorimetry
cryometric method
Pokaż więcej
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:
https://bibliotekanauki.pl/articles/358605.pdf  Link otwiera się w nowym oknie
Opis:
Hexabenzylhexaazaisowurtzitane (HBIW) is produced by a condensation reaction of benzylamine with glyoxal in suitable organic solvents in the presence of protonic acid catalysts. Impurities have to be removed prior to the subsequent stages of the synthesis of CL-20. The effectiveness of HBIW purification by recrystallization from a variety of solvents has been studied here. This method was compared with a novel approach suggested for HBIW purification that consists of prolonged heating of the crude product in boiling methanol. This new purification method allows the product to be prepared in satisfactory purity, it is simple and easily performed on a large-scale.
Dostawca treści:
Biblioteka Nauki
Artykuł

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