关键词: supercritical carbon dioxide;microparticle;recrystallization rate;1;3;5;7-tetranitro- 1;3;5;7- tetraazacyclooctane, 3, 5, 7- tetraazacyclooctane

Abstract: Microparticle formation and crystallization rate of 1,3,5,7-tetranitro-1,3,5,7-
tetraazacyclooctane (HMX) in acetone solution using supercritical carbon dioxide
antisolvent (GAS) recrystallization were studied. Scanning electronic microscopy, X-ray
diffraction and infrared radiation were used to examine particle size, crystallinity and
chemical structure. The results show that β-HMX microparticle in different average size
(2-9.5μm) and with narrow size distribution were obtained by controlling the
expansibility, expansion speed, initial concentration and temperature during
recrystallization of HMX. The formation of nuclei may be a main cause of consumption of
solute when the solution is expanded rapidly enough and the equilibrium concentration is
lower, in which almost monodisperse microparticle can be obtained.

Key words: supercritical carbon dioxide, microparticle, recrystallization rate, 1, 3, 5