Thin-film methods for examining the decomposition chemistry of explosives

Experimental techniques using thin-film samples and infrared spectroscopy have been developed to examine thermally-induced condensed-phase decomposition chemistry of explosives. Experiments with nitrocellulose (NC) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) were done to examine the effects of confining the decomposition proucts so that intimate contact was maintained with the remaining explosive during isothermal decomposition at temperatures below those of the respective DTA exotherms. The NC experiments showed that substantial NC decomposition occurred at 150C and confinement of the decomposition products influenced the decomposition reactions. Some of the mechanisms and reaction rates with confined samples compared favorably with published mechanisms and rates from unconfined samples, while other mechanisms and reaction rates differed. The TATB experiments showed that significant TATB degradation occurred at temperatures as low as 210C, and substantial degradation occurred within 24 hours at 250C which is about 80C below the temperature of the DTA exotherm for TATB.