Aqueous density fractionation of nanocarbons from colliding-wave PBX9502 detonation soot

The study of solid carbon (nanocarbon) nucleation and growth from detonating high explosives is limited because of the difficulty directly evaluating chemical reactions behind the shock front. Understanding the correlation between detonation conditions and nanocarbon formation requires isolation, purification, and analysis of the carbon products. Aqueous density fractionation of products recovered from a colliding wave TATB-based high explosive (PBX9502) detonation are evaluated as an environmentally benign, "green" chemical processing approach for the separation of carbon materials from metal and metal oxide byproducts. Recovery of material sufficient for X-ray scattering analysis was obtained in two fractions. X-ray scattering showed the less dense fraction (ρ < 1 g/cm3) contains hollow spherical core (davg = 27.8 nm) nanoparticles with a shell (thickness=3.6 nm) composed of predominately sp2 hybridized carbon. Particles contained within the dense fraction (ρ > 1 g/cm3) were a mixture of oblate spheroids (major axis length=43.8 nm and minor axis=2.9 nm) and small polydisperse solid spherical particles (davg = 2.4 nm) composed of both sp2 and sp3 bonded carbon with residual contamination from the brass detonators.