Precise assay of TATB by the determination of total amino and nitro functional groups

Methods have been developed for the precise assay of the explosive l,3,5-triamino-2,4,6-trinitrobenzene (TATB) using procedures that quantitatively measure total nitro and/or total amino functional groups. The method for the determination of total nitro groups is based on the dissolution of TATB in DMSO-NaOH, electrolytic reduction of -NO₂ to -NH₂, and measurement by controlled-potential coulometry. The reduction is carried out at a mercury pool electrode at −0.60 V versus standard calomel electrode (SCE) in a supporting electrolyte 1 M in H₃PO₄ and 3 M in HClO₄. Background corrections are low, and samples containing 0.1 mg to 2 mg of TATB per ml can be analyzed with a precision and accuracy of 0.25% to 0.5%. The method for determining total amino groups is based on the conversion of -NH₂ to NH₃ in a Kjeldahl-type apparatus. The sample does not require an acid digestion step. The - NH₂ groups are readily converted to NH₃ and distilled from a solution of NaOH and dimethylsulfoxide (DMSO). Individual samples of 120 mg-170 mg of TATB can be conveniently assayed for amino groups with an accuracy and precision of about 0.25%.     

Dielectric relaxation spectroscopy of sheet molding compound

Dielectric relaxation spectroscopic studies of sheet molding compound from 400 Hz to 100 kHz reveal the relaxation processes that exist in this material. The frequency dependence of SMC is presented and analyzed in terms of different relaxation process models. A transition map of SMC is presented.