Evaluation of Ultrasonic Treatment for the Size Reduction of HNS and HMX in Comparison to Solvent‐Antisolvent Crystallization

Kaur, Jatinder; Arya, Vandana Pathania; Kaur, Gurvinder; Raychaudhuri, Tusharkanti; Lata, Prem

doi:10.1002/prep.201100072

Cited by 11 publications

(12 citation statements)

References 8 publications

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“…Purified HNS (mean diameter 90 mm with a range up to 600 mm) was dissolved at 10 g in 400 ml DMF (N, N-dimethylformamide) by heating to 65 8C and the HNS-DMF solution was filtered to remove any suspended material. Previously we had followed drowning out crystallization (designated as method 1) to make fine HNS wherein concentrated HNS solution in DMF (4 g in 80 ml) was poured slowly in a thin stream into the antisolvent water [13] which resulted in HNS of average diameter in submicron scale with a range extending to few microns and contained HNS particles not having nanoscale distribution. Subsequently in the present work in order to see the feasibility to make nano-scale HNS in bulk, this process was modified (designated as method 2) in antici-pation of having further lower particle size product and better control on a batch to batch size variation.…”

Section: Solvent-antisolvent Crystallizationmentioning

confidence: 99%

“…It was used in solvent-antisolvent crystallization. For exploring the nano HNS preparation by solvent-antisolvent crystallization (UF-HNS) in bulk we modified the previously reported process [13] as our purpose was to standardize the method at least at a few grams scale per batch at the laboratory level. Dilute solution of HNS is desirable to make very fine nano-size particles but the good yield is also desirable.…”

Section: Particle Size and Morphologymentioning

confidence: 99%

“…D 90 of the particles was~1 mm. This modification of the solvent antisolvent crystallisation process by using dilute solution and narrow passage (method 2) resulted in production of HNS (UF-HNS) that was helpful in giving advantage in making slightly more finer submicron UF-HNS than when the process involved pouring a concentrated HNS-DMF solution (4 g in 80 ml) slowly into the antisolvent (method 1) reported previously [13]. SEM analysis (Figure 4) showed the presence of some nano size HNS particles among the comparatively larger particles.…”

Section: Particle Size and Morphologymentioning

confidence: 99%

“…However, too diluted solutions of explosives will result in a very large volume of solvent-antisolvent mixtures that need to be handled to separate out the material with a very low yield of nano-size HNS, which is [ not very suitable for practical considerations of upscaling the production. Mechanical methods of particle size reduction include grinding by ultrasonication, ball mill, and fluid energy mill which do not require high boiling point solvents [10,[13][14][15]. However, these methods also produce particles mostly in the micron-size range and not in the nano-scale range when the starting material is coarser post-production grade which may be usually of the range of more than hundred microns.…”

Section: Introductionmentioning

confidence: 99%

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Size Reduction of HNS to Nanoscale by in Tandem Application of Chemo‐mechanical methods

Pandita

Arya

Kaur

et al. 2019

Propellants Explo Pyrotec

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The present study was undertaken to evaluate and compare the extent of particle size reduction of HNS and its characterization by applying sequentially the solvent based crystallization, ultrasonication, and ball‐milling. It was found that submicron ultrafine HNS (UF‐HNS) of mean diameter ∼0.5 μm with a size range extending to micron scale (∼3 μm) was produced by the solvent‐antisolvent crystallization process. This HNS was subsequently subjected to long duration ultrasonication up to 28 h and planetary ball milling up to 8 h. The HNS particles were characterized for morphology and particle size by scanning electron microscope (SEM), laser diffraction‐based and dynamic light scattering based particle size analyzer (PSA). The structural analysis was done by FTIR and thermal stability by the thermo‐gravimetric analyzer (TGA). The residual solvent content was estimated by headspace GC‐MS. Impact and friction sensitivity were evaluated by BAM fall hammer and friction sensitivity tester. Compared to ultrasonication varying from 4 h to 28 h, planetary ball milling of the micron‐sized HNS caused the size reduction to maximum extent and resulted in production of nano‐scale HNS (∼300 nm average diameter) with a very narrow size distribution of less than 1 μm which had lower impact sensitivity, thermal stability and lesser residual solvent content compared to micron‐sized HNS (UF‐HNS). Thus, nanoscale HNS with a very narrow size distribution was produced by application of the mechanical method of ball milling sequentially to the solvent based crystallization process.

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Section: Solvent-antisolvent Crystallizationmentioning

confidence: 99%

Section: Particle Size and Morphologymentioning

confidence: 99%

Section: Particle Size and Morphologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Size Reduction of HNS to Nanoscale by in Tandem Application of Chemo‐mechanical methods

Pandita

Arya

Kaur

et al. 2019

Propellants Explo Pyrotec

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“…Kaur et al has evaluated ultrasonic treatment method with solvent-anti-solvent method for size reduction of HNS and HMX. It was observed that solvent and anti-solvent method produced HNS with size distribution up to 3 mm [18]. So it is seen from literature that many methods have been developed to prepare submicrometer explosive particles with tunable properties such as particle size, morphology and uniform size distribution.…”

Section: Introduction and Literature Reviewmentioning

confidence: 99%

Micro Nozzle Assisted Spraying Process for Re‐crystallization of Submicrometer Hexanitrostilbene Explosive

Gupta

Kumar

Jindal

et al. 2018

Propellants Explo Pyrotec

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Hexanitrostilbene has excellent thermal and shock stability, and shelf life. It has reliable initiation functioning when subjected to short duration pressure pulse stimuli. These characteristics make it one of the potential explosives for miniature devices such as exploding foil initiators, through bulkhead initiator, and fuzes for high ‘g’ applications. It also finds wide application in devices used for civilian applications such as mining and oil exploration. However, preparation of submicrometer HNS (sm‐HNS) explosives and batch‐to‐batch variation is a challenging task in terms of filtering, repeatability of particle size and shape distribution. In our research work, micro nozzle assisted spraying process (MNASP) was developed. The MNASP setup consists of micro fuel nozzle, pressure cylinder for HNS solution, flow meter and pressure gauges. The process attributes such as stirring rate, pressure, temperature, nozzle diameter, flow rate, ultra‐sonication frequency were optimized using weighted average method of Analytical Network Process (ANP) techniques. Laser diffraction‐based particle size analysis showed that sm‐HNS in the range of 300 to 700 nm, with average particle size of 515 nm and narrow standard deviation of 34 nm can be obtained using this process with very high consistency in batch‐to‐batch preparation. 1H NMR investigations were carried out to confirm the purity of sm‐HNS. FTIR spectra confirmed the structure of sm‐HNS. The process is a unique laboratory scale table‐top pilot plant which is highly repeatabe under same conditions, and cost‐effective for large scale production at the rate of 50 grams per hour. The advantage of consistency in preparation of sm‐HNS with narrow particle size distribution is observed in performance of exploding foil initiators. There is consistency in threshold firing voltage of 1.5 kV, with standard deviation of 147 V.

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Taguchi Optimization of Solvent‐Antisolvent Crystallization to Prepare Ammonium Perchlorate Particles

et al. 2020

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The sphericity and size of ammonium perchlorate (AP) particles significantly influence the properties of composite propellants. As the AP particles become more spherical, the accumulation coefficient increases, the viscosity during casting decreases, and the particle loading and burning rate increase. Hence, the production of micronized AP particles with an average size between 1 and 20 μm is important to increase the loading percentage of AP in the composite propellant. Here, the Taguchi experimental design was used to optimize the solvent-antisolvent crystallization (SAC) process for the preparation of micronized AP particles with higher sphericity. SAC parameters such as the type of antisolvent, the solvent-to-antisolvent ratio, the antisolvent temperature, the stirring speed, and the retention time were investigated at four levels. The type of antisolvent and the solvent-to-antisolvent ratio were found to mainly contribute to improving the sphericity and size of the AP particles, respectively.

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Evaluation of Ultrasonic Treatment for the Size Reduction of HNS and HMX in Comparison to Solvent‐Antisolvent Crystallization

Cited by 11 publications

References 8 publications

Size Reduction of HNS to Nanoscale by in Tandem Application of Chemo‐mechanical methods

Size Reduction of HNS to Nanoscale by in Tandem Application of Chemo‐mechanical methods

Micro Nozzle Assisted Spraying Process for Re‐crystallization of Submicrometer Hexanitrostilbene Explosive

Taguchi Optimization of Solvent‐Antisolvent Crystallization to Prepare Ammonium Perchlorate Particles

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