Exploring interface dynamics in plastic bonded-explosives: synthesis, characterization, and neutron reflectometry

Understanding the interfacial properties of high energy explosives blended with polymer binders is important for optimizing material performance and predicting aging. In the case of PBX 9502, direct measurements of the TATB – Kel-F 800 interface have been limited by the lack of high-fidelity model systems. This paper reports the fabrication of a new thin film, model TATB sample to enable neutron reflectometry measurements of this interface. The fabricated TATB films were characterized using X-ray diffraction, scanning electron microscopy, and atomic force microscopy. The film deposits in the same polymorph as the TATB crystallites in PBX 9502, but in the form of highly textured nanopillars that are ~200 nm wide. The buried interface of the TATB film (i.e., bottoms of the pillars) has an rms roughness of ~3 nm and is the (001) crystal face. The TATB films retain their features when deposited on Kel-F 800 thin films, enabling the formation of layered PBX 9502 model samples. Neutron reflectometry measurements showed increasing roughness of the TATB – Kel-F 800 interface with thermal aging, consistent with void formation at this interface.