TATB decomposition temperature

Table 6 compares the Small Scale Safety Test (SST) values for RX-55-AE-5, PBX 9502, LX-17, TATB and LLM-105 determined in this work. Thermal decomposition is used to determine the thermal stability of a material with respect to heat [16]. TATB compounds are well known for their stability towards heat and are known to decompose at higher temperatures from 370 to 385°C. In Figure 10 we have overlaid thermal decomposition scans of RX-55-AE-5 with PBX 9502 and LX-17 to be compared for thermal stability. RX-55-AE-5 shows a broad decomposition peak. It is not understood why the decomposition peak is so broad and appears to have at least two peaks present. It is clear that the base of the decomposition peak is approximately 10°C broader than for PBX 9502 and LX-17. The RX-55-AE-5 sample decomposition temperature appears to be approximately 27°C lower than LX-17 and 25°C lower than PBX 9502. 

The characteristics of this explosive are calculated density (X-ray diffraction) =1.865gem"3, impact sensitivity (h50% for 5 kg weight) =70cm, friction sensitivity = insensitive, temperature of decomposition (DSC) ca. 350°C and VOD = 8200 ms"1. The data confirm that DANTNP is slightly more powerful while its impact insensitivity is of the order of TATB [174]. 

Figure 20 has been taken from [9] and presents Eq. 8 in which the Ea values resulted from the Russian manometric method for polynitro arenes and Qreai values were calculated according to the Pepekin et al. semi-empirical method [157]. It must be stated that the value of TATB, obtained on the basis of the Russian manometric method (i.e. in vacuum, see [151]) in a temperature region above its hypothetical melting point [171], correlates with the data for thermal decomposition in the Uquid state (this Ea value, which is very close to the heat of sublimation of TATB, is discussed in [171]). The data of TATB obtained from DSC (see [151], i.e. from measurements at atmospheric pressure) logically correlate with DATB and PAM data in Fig. 20. 

Los Alamos National Laboratory, was used for impact experiments. The samples yielded smooth DTA and pyrolysis curves indicating no peaks or changes below their normal temperatures of decomposition. On washing the control TATB samples with acetone, no ragged holes or micro-cavities appeared under the SEM due to impurity extraction. The samples of TNT, HMX, RDX and other explosives used, were also the best samples available from various laboratories. 

The density and mass fraction of undecomposed explosive cross sections through i=ll are shown at various times for TATB with a matrix of 0.005-cm-radius holes at 27°C in Figure 3.30, and at 75°C in Figure 3.31. The amount of decomposition increases with temperature with propagation of detonation occurring at 75°C. The detonation occurs more quickly at 250°C than at 75°C. 

The 40 kbar shock wave collapsed the hole and formed a small, weak hot spot that was not hot enough to result in appreciable decomposition of the TATB. The 290 kbar shock wave temperature was not hot enough to cause explosion during the time studied in the bulk of the explosive previously shocked to 40 kbar however, the additional heat present in the hot spot formed by the 40 kbar shock wave after it interacted with the hole was sufficient to decompose some of the explosive after it was shocked by the 290 kbar wave. Propagating detonation occurred immediately after the 290 kbar shock wave caught up with the 40 kbar preshock. 

To model desensitization by preshocking, the modification indicated by the three-dimensional study, described in Chapter 3, to the Forest Fire decomposition rate was to limit the rate by the initial shock pressure and to add the Arrhenius rate law to the limited Forest Fire rate. The Forest Fire rate for TATB is shown in Figure 4.21, along with the Arrhenius rate calculated using the temperatures from the HOM equation of state for the partially burned TATB associated with the pressure, as determined by Forest Fire. The multiple shock Forest Fire model (MSFF) uses a burn rate determined by Forest Fire, limited to the initial shock pressure, and the Arrhenius rate using local partially burned explosive temperature. 

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