427862 Investigation of the Formation of Nanoscale 2CL-20 HMX Cocrystal

Thursday, November 12, 2015: 9:15 AM
155D (Salt Palace Convention Center)
Hongwei Qiu1, Rajen B. Patel2, Reddy Damavarapu3 and Victor Stepanov2, (1)Leidos Inc., Picatinny Arsenal, NJ, (2)US Army, RDECOM ARDEC, Picatinny Arsenal, NJ, (3)US Army, ARDEC, Picatinny Arsenal, NJ

Energetic nanoscale 2CL-20∙HMX, a cocrystal of CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane) and HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocine) at a 2:1 molar ratio, was prepared by a novel method of bead milling an aqueous suspension of ε-CL-20 and β-HMX. Conversion of the coformers to the cocrystal form was monitored by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis of specimens sampled at various milling times. Complete conversion to the cocrystal form was achieved. Rounded 2CL-20∙HMX cocrystal particles with a mean size below 200 nm were produced. The conversion was further studied by varying the processing variables. A mechanism for the conversion of the coformers to the cocrystalline form is postulated based on the experimental results. As an inherently safe manufacturing method, the aqueous bead milling process has a great potential in advancing the cocrystal research and applications in the field of energetic materials.

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