Microstructural Differences between Virgin and Recycled Lots of PBX 9502

PBX 9502 is an insensitive high explosive formulated comprised of 95 wt% TATB and 5 wt% Kel‐F 800^TM binder. Due to the relatively high cost of manufacturing TATB (triaminotrinitrobenzene), methods for reclaiming TATB from PBX 9502 machine cuttings were previously developed. Reclaimed PBX 9502 was mixed with ~ 50% virgin PBX 9502 to produce “recycled” lots of PBX 9502. Several studies have shown significant differences between the mechanical properties of virgin and recycled lots of PBX 9502, and postulated that the differences were related to various aspects of TATB particle size and distribution. The purpose of this study is to show that these differences in mechanical properties are related to differences in the distribution of TATB within the microstructure of PBX 9502. Ultimately, a better understanding of these properties may lead to selected formulation changes for future rebuilds, Lifetime Extension Programs (LEP) and/or candidate replacements to enhance engineering and physics performance.