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Wyświetlanie 1-5 z 5
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.
Powiązania:
https://bibliotekanauki.pl/articles/951498.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
CL-20
polymorphs
α-CL-20 impurity
Dispersive Raman Spectroscopy
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%.
Źródło:
Central European Journal of Energetic Materials; 2013, 10, 3; 419-438
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Towards New Directions in Oxidizers/Energetic Fillers for Composite Propellants: an Overview
Autorzy:
Dey, A.
Sikder, A. K.
Talawar, M. B.
Chottopadhyay, S.
Powiązania:
https://bibliotekanauki.pl/articles/358191.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
binder
oxidizer
composite propellant
burn rate modifier
plasticizer
high energy materials
Opis:
There is continued interest in the development of safe and reliable composite propellant formulations using modern energetic ingredients such as energetic oxidizers/energetic ingredients, energetic binders, and energetic ballistic modifiers. There are continued efforts by energetic materials researchers, scientists, technologists and engineers to design composite propellant formulations with better ballistic properties than conventional formulations. The efforts in many research and development (R & D) laboratories all over the world are aimed at utilizing modern oxidizers/ energetic fillers for the development of composite propellant formulations for both space and defence applications. Composite propellants are considered to be the major source of chemical energy for rockets and missiles. Energetic oxidizers/fillers play vital roles in the preparation or manufacture of composite propellant formulations. Various energetic oxidizers/fillers have been developed during the last five decades to address environmental safety, high energy and processing conditions. In this article, the authors have reviewed the characteristic properties of the energetic oxidizers/fillers used in the preparation of composite propellants. The characteristic properties of the energetic ingredients play an important role in the preparation of composite propellant formulations with the desired mechanical properties. The advantages and disadvantages of various energetic oxidizers/ingredients for specific and potential propellant applications are also highlighted throughout the course of this review article. The future direction in composite propellant formulations calls for the development of green propellant formulations. Efforts will continue to seek alternative and more energetic oxidizers/fillers in comparison to conventional oxidizers. There is an urgent need to replace conventional oxidizers such as ammonium perchlorate with eco-friendly ingredients.
Źródło:
Central European Journal of Energetic Materials; 2015, 12, 2; 377-399
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Method of Producing Uniformly Shaped and Sized Particles of 2,4,6-Triazido-1,3,5-triazine by Emulsion Crystallization
Autorzy:
Anniyappan, M.
Sonawane, S. H.
Shee, S. K.
Sikder, A. K.
Powiązania:
https://bibliotekanauki.pl/articles/358545.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
cyanuric triazide
emulsion crystallization
spherical free-flowing crystals
green primary explosive
Opis:
Generally, 2,4,6-triazido-1,3,5-triazine or cyanuric triazide (CTA) is obtained from the synthetic process as long, sharp edged crystals or fine/ agglomerated particles. These are very sensitive and not suitable for detonator filling, leading to poor performance. We report herein a method for the preparation of uniformly shaped and sized particles of CTA with a free-flowing crystalline nature suitable for detonator applications. The uniformly shaped free-flowing CTA crystals are obtained by emulsion crystallization using a non-solvent at elevated temperature. The free-flowing CTA particles prepared were characterized using spectroscopy, SEM, and particle size analysis techniques. The results show that the CTA crystals obtained by emulsion crystallization are smooth surfaced, nearly spherical grains with a free-flowing nature. Furthermore, the results show that CTA crystals have a higher bulk density (BD) compared with normal CTA crystals prepared by crash precipitation. The thermal behaviour of the CTA crystals obtained by emulsification crystallization was investigated by conducting experiments such as DSC and using an explosion temperature tester.
Źródło:
Central European Journal of Energetic Materials; 2015, 12, 4; 785-797
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improvements in the Structural Integrity of Resin Based Combustible Cartridge Cases (CCC) at Elevated Temperatures
Autorzy:
Dey, A.
Athar, J.
Gogoi, S.
Navle, P. B.
Sikder, A. K.
Powiązania:
https://bibliotekanauki.pl/articles/357926.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
CCC
deformation
PVAc
ammunition
cartridge
gun
Opis:
An advanced, solvent-less resin based Combustible Cartridge Case (CCC), designed to resolve the inherent problems of shrinkage and limited mechanical strength associated with the gelatinisation of nitrocellulose, has already been developed. The felt-moulded components contain thermoplastic polyvinyl acetate (PVAc) resin as the binder and the enhanced mechanical strength is achieved by carrying out hot compaction of dry felts at an elevated temperature (105 ± 2 °C). Presently, resin based technology is adopted for tank gun ammunition and also for the developed modular CCCs, i.e. the Modular Combustible Case (MCC) for different types of artillery gun ammunition. However, during exhaustive trials conducted with the resin based CCCs in 120 mm tank gun ammunition at three temperatures, i.e. -10, 27 and 55 °C, severe geometrical deformation was noticed when the rounds were conditioned at 55 °C for 24 h., adversely affecting the loading of rounds into the gun chamber. This was attributed to the combined effects of softening of the resin at that temperature and the load of the projectile/ shell (14.4 kg) experienced by the CCC region during conditioning of the round in the horizontal mode. In order to resolve this problem of deformation, PVAc resin was required to be modified. The PVAc resin was modified to the form of a nanocomposite. PVAc nano composite was prepared by dispersing organically modified nano clay, i.e. Cloisite 30B, into the resin before making the CCCs. The nanocomposite of PVAc resin was characterized by FTIR, DMA, softening point measurement etc. The results showed a remarkable improvement in the glass transition temperature (Tg) and in the softening temperature of the modified PVAc resin. This modified PVAc resin was used to prepare CCCs. Furthermore, these CCCs were coated with hexamethylene diisocyanate (HMDI) on the inner and the outer surfaces. The isocyanate coating becomes crosslinked in the matrix, thereby improving the softening point as well as the mechanical properties of the CCCs. These modified CCCs were repeatedly tested at 55 and 60 °C for 24 h. After testing, it was found that no deformation had taken place and the assembled rounds were easily loaded into the gun chamber. The use of the PVAc nanocomposite in the preparation of resin based CCCs, followed by isocyanate coating, is an effective means of achieving the required improvement in structural integrity of the resin CCCs at elevated temperatures.
Źródło:
Central European Journal of Energetic Materials; 2015, 12, 1; 117-127
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies on the Tailoring of Particle Size and Micromeritic Properties of Reduced Shock Sensitivity RDX (RSS-RDX)
Autorzy:
Ramavat, V.
Sarangapani, R.
Reddy, S. T.
Patil, R. S.
Gore, G. M.
Sikder, A. K.
Powiązania:
https://bibliotekanauki.pl/articles/951500.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
crystallization
RSS-RDX
micromeritics
particle size distribution
Opis:
The microstructure of explosive particles, as well as formulations, has a significant influence on the shock sensitivity of various energetic formulations. Particle shape and specific size distributions are always important considerations in explosives processing in order to realize better process parameters. The present study aimed to explore crystallization variables required to achieve a specific particle size of Reduced Shock Sensitivity RDX (RSS-RDX). Crystallization process factors such as cooling rate, agitator speed and configuration, etc. have been systematically studied to understand their effect on the particle size. The study also established the crystallization process parameters required to tightly control a specific particle size distribution ranging from 50 to 500 μm by cooling crystallization. Fine particles ranging from 15 to 30 μm were prepared by an ultrasonication technique. Ultrasonic process parameters, including temperature, time and ultrasonic frequency, were studied and the process conditions were optimized. Micromeritic characterization of RSS-RDX revealed the nature of flowability, which in-turn is useful in identifying the ease of processability. Overall, our interest stemmed from an investigation which showed that careful optimization of crystallization variables can lead to a specific particle size distribution.
Źródło:
Central European Journal of Energetic Materials; 2013, 10, 4; 581-592
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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