Asymmetrical Flow Field-Flow Fractionation for Characterization of Cyclotrimethylene Trinitramine (RDX) Particles Prepared by Supercritical Anti-Solvent Recrystallization

Prospective Symbiosis of Green Chemistry and Energetic Materials

“…Under thesec onditions (CHN, HMX concentration 3.5 mol L À1 ,s olution rate 3mLmin À1 , and CO 2 rate 70 mL min À1 ), the authors managed to obtain spherical particles of HMX with 56 nm diameter,w hich was impossible before the optimization. Dou et al [233] added an ew parameter,t he pressure drop (PressD) on the nozzle, to describe the SAS processing of RDX adequately.I nt heir experiments,a20 %s olution of RDX in DMF was injected into av essel at a2 5mLmin À1 flow rate, 10 MPa, and 40 8Cw ith aC O 2 feed rate of 25 mL min À1 .T he variation of PressD (0, 4.5, and 11 MPa) by changing the nozzle length afforded RDX particlesw ithm eans izes of 13.1, 11.6, and 8.7 mm, respectively.M oreover,t he authors managed to obtain even 5.9 mmp articles of the same HEM using PressD of 15 MPa. [234] SEM and opticalm icroscopy images were used to show that ah igher PressD led to rounder and regular crystals, as hape that is always preferable for HEMs.…”

Supercritical carbon dioxide assisted formation of crystalline materials for various energetic applications

“…RDX microparticles efficiently formed from saturated dimethylformamide solution via the SAS procedure. 90,91 The finest particles could be obtained in the reactor equipped with a nozzle of a smaller diameter resulting in a higher pressure drop. In some cases, even a narrow capillary created a sufficient pressure drop and could be used instead of a nozzle to produce RDX particles of 6-7 um (Fig.…”

Colloidal nanoparticles produced from Cu metal in water by laser ablation and their agglomeration

“…Detailed instrumentations and the detection methods of LIBD and FFF are in described previous published papers (Jung et al, 2009;Dou et al, 2012). For transmission electron microscopy (TEM, JEOL JEM-2100F, Field Emission Electron Microscope) including an energy dispersive X-ray (EDX) analyzer, samples were immediately prepared by putting a drop of each aqueous solution containing nanoparticles as produced after the laser ablation of 25 min, onto a 200 mesh copper carbon only grid and then allowing the solvent to evaporate in air.…”