Preparation and Thermal Decomposition of CL-20-based Cocrystals Using Resonant Acoustic Mixing. (English)

High-energy insensitive energetic materials were essential to develop future rockets, strategic/tactical missiles and space vehicles. Three CL-20-based cocrystals including CL-20/2-mercapto-1-methylimidazole, CL-20/4-methyl-5-nirroimidazole, and CL-20/caprolactam have been prepared by using Resonant Acoustic Mixing (RAM) technique, and their structures, morphology, thermal decomposition and ignition were studied by using PXRD, SEM, TG-DSC, TG-MS, and laser ignition apparatus. The results show that the first two cocrystals could be obtained after mixing for 15 min under the acceleration of 70 g and tiny solvents, and CL-20/caprolactam cocrystals were prepared successfully after mixing for 30 min under the same condition. It was found that the RAM could use the same solvents to the solvent evaporation method, and the volume of solvents was less compared to the solvent evaporation method, and the reaction time was also shorter. It can be seen from the SEM images that the cocrystal particles vary in size and shape. The decomposition peak temperature for these three CL-20 cocrystals was lower than that of the CL-20, and the thermal decomposition process, heat release, and decomposition products were strongly related to the melting temperature and initial decomposition temperature of the crystallization molecules. The CL-20/4-methyl-5-nirroimidazole cocrystal exhibited a faster decomposition rate and larger heat release than CL-20, and the decomposition gas products of these cocrystals exhibited the increase of CO2 and water vapor. After the CL-20 was crystallized, the ignition delay time and flame propagation have been affected, and the combustion of the CL-20/caprolactam with the high carbon content was more complete, and the flame was also lighter, and higher intensity. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Explosives & Propellants is the property of Chinese Journal of Explosives & Propellants Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)