Effects of Low-Level Gamma Radiation on Common Nitroaromatic, Nitramine, and Nitrate Ester Explosives

Abstract

The aging of high explosives in an ionizing radiation field is not well understood, and little work has been done in the low dose and low dose rate regime. In this study, four explosives were exposed to low-level gamma irradiation from a 137Cs source: PETN, PATO, and PBX 9501 both with and without the Irganox 1010 stabilizer. Post-irradiation analysis included GC–MS of the headspace gas, SEM of the pellets and powder, NMR spectroscopy, DSC analysis, impact sensitivity tests, and ESD sensitivity tests. Overall, no significant change to the materials was seen for the dose and dose rate explored in this study. A small change in the 1H NMR spectrum of PETN was observed and SEM and ESD results suggest a surface energy change in PATO, but these differences are minor and do not appear to have a substantial impact on the handling safety.

Radiolytic degradation of dodecane substituted with common energetic functional groups

“…The largest contributor was nitrous oxide at 39 mol%, followed by an amine at 24 mol%. Nitrous oxide has also been seen as a major component in the gas phase of irradiated explosives 23–25 containing the nitro energetic FG, so this result was expected. Overall, these results indicate that D–NO 2 is a relatively stable molecule to irradiation when compared to the other molecules used in this study, though degradation of the nitro energetic FG is a large contributor to the degradation gas products observed.…”

“…Interestingly, the order of the results matches well with both photolytic molecular dynamics simulations of these molecules at 8 eV 14 as well as the general trend for the sub-shock impact sensitivity of various explosives. [31][32][33] Although a more limited study, these results also provide an explanation why, for a previous study exploring radiolytic damage to a variety of explosives, 25 the only explosive that was found to degrade with low-level radiation in large enough quantities to be detectable using 1 H-NMR spectroscopy was pentaerythritol tetranitrate (PETN), a nitrate ester-based explosive. The total gas yields, however, are a measure of how radiolytically active the entire molecule is rather than just the energetic FG.…”

“…As mentioned earlier in the text, D-ONO 2 was found to degrade only along the O-NO 2 bond which is the trigger linkage for the nitrate ester FG. This bond has also been found to be particularly susceptible to damage in radiolytic, 23,25 thermal, [39][40][41] and explosive insult 42,43 degradation events. No instances were observed with the loss of -ONO 2 ; instead, the damage to the nitrate ester FG appears to be exclusively through the N-O bond.…”

“…This result also follows for what is currently known about the radiolysis of explosives: most of the degradation occurs not on the carbon molecular structure supporting the energetic FGs, but rather on the energetic FGs themselves, and particularly along the trigger linkage. 23,25,44…”

Chemical Evaluation and Performance Characterization of Pentaerythritol Tetranitrate (PETN) under Melt Conditions

“…The degradation of PETN has been studied extensively, , with detailed investigations on decomposition by acid, metal oxides, , impurities, and radiation − and biological, , explosive, and thermal − insults. The O–NO 2 bond in the nitrate ester of PETN is the weakest in the molecule, and it is generally accepted that this bond is the first to break during both slow decomposition − and fast decomposition found in detonations .…”