Production of HMX crystals with high internal quality by cooling crystallization

The crystn. of HMX from solns. by cooling was studied as to the prodn. of crystals with little defects and explosives of low vulnerability. Influences of solvents, stirrer design and speed, and cooling rate were studied. Vulnerability was tested using hydroxy-terminated polybutadiene-bonded formulations. Samples obtained by crystn. from propylene carbonate showed the desired crystal shape, size, purity, and surface properties and essentially decreased vulnerability. Other solvents tested were cyclohexanone, DMF, and N-methylpyrrolidone. A relationship between particle d. and vulnerability was found.