Mechanical and Explosive Performance Modifications of PBXs via Biologically Inspired Core-shell Surface Coating

Plastic-bonded Explosives (PBXs) are a unique class of highly loaded particle composites. As in the majority of these composite systems, mechanical failure is observed at the interface between the filler particles and the polymer binder system. To prevent this interfacial failure and to strengthen the entire composite system, polydopamine (PDA), a biologically inspired polymer rich in catechol groups, is deposited on the surface of the filler material. PDA is formed through the oxidative degradation of dopamine that results in monomers capable of forming a robust cross-linked, core-shell structured film on the surface of the filler particles. The film is formed without chemically bonding to or modification of the underlying crystal structure. PDA has been applied to a wide range of explosive formulations and shows a dramatic mechanical strengthening effect. However, little work in the literature has demonstrated the effects of PDA coating of explosive crystals on the detonation performance and safety of a PBX. In this work, we investigate PBX 9501 modified with core-shell PDA films, and the resulting effect on mechanical strength as well as safety and detonation performance. LA-UR-22-21842.