Analysis of ultrafine TATB by ultrasonic-assisted equilibrium headspace analysis

The purpose of this work was to screen different lots of ultrafine 1,3,5-triamine 2,4,6-trinitrobenzene (TATB) for chemical differences, which may include synthesis and formulation byproducts, decomposition products, and contaminants. The approach used here permits analysis of trapped species as volatile and semivolatile chemicals within a solid. This procedure involves preconcentration of species from the TATB matrix into a surrounding headspace followed by a preconcentration and collection step using solid phase microextraction (SPME) collection. The sample is prepared by sealing it in a glass ampule with a few milliliters of water, ultrasonicating the solution, and then sampling the headspace using SPME collection. Water couples in the ultrasonic energy to fracture the TATB, which permits the release of nonpolar species into the gas phase. However, polar species will favor the aqueous phase and require a separate analysis procedure, which is not included here. Following SPME collection, the sample is transferred to a gas chromatography/mass spectrometer (GCMS) for analysis. In this work, we analyzed and interpreted outgas signatures from four different lots (1169-135MPS-001, 4271-135M-002, 91190-135M-003, and 98170-135M-001) of ultrafine TATB. Lot 98170-135M-001 is a reprocessing of Lot 4271-135M-002, which was washed to remove the water-soluble polysaccharides. The pedigree for these materials are foundmore » in a memo from Tom Stallings and Gordon Osborn of Mason & Hanger Co., Pantex Plant in the Appendix section. Nominally, ultrafine TATB is synthesized via the emulsion-amination method in which an emulsifier is included during the amination of the 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) precursor. The ultrafine TATB formulation also includes 0.2% by weight guar gum, a galactomannan polysaccharide, to enhance flow properties. Historically, this polysaccharide was added to PETN to reduce its sublimation temperature, but it was also found to enhance flow characteristics, thus improving processing.« less