Analysis of Slurry-Coating Effectiveness of CL-20 Using Grazing Incidence X-ray Diffraction.

A grazing incidence X-ray diffraction technique was developed to characterize the effectiveness of the coating of the solid particles by the binder in energetic formulations and was used in conjunction with scanning electron microscopy, traditional wide-angle X-ray diffraction, and specific gravity measurements to probe the microstructure of PAX-12 granules. The grazing incidence X-ray technique was applied to granules formed upon slurry coating and indicated different X-ray scattering characteristics for high- and low-sensitivity granules, suggesting significant differences in the distribution of the binder at the surface of the granules. The granules were made by slurry-coating crystals of epsilon CL-20 with cellulose acetate butyrate, a binder, and bis-(2,2 dinitropropyl acetal/formal), a plasticizer. Granules with high sensitivity to impact and friction were shown to have an interior that was relatively porous and that consisted of uncoated CL-20 crystals. Their surface had regions with a thick layer of coating material and other regions of uncoated crystals. Granules that showed a low sensitivity to impact and friction had coated CL-20 crystals throughout their interior and on the surface. [ABSTRACT FROM AUTHOR]