Study of initiation reactivity of some plastic explosives by vacuum stability test and non-isothermal differential thermal analysis

Abstract

On the basis of measurements of 18 high explosives by means of the Czech Vacuum Stability Test (VST) STABIL, a relationship has been specified between the results of this test and those of Russian manometric method. The said relationship was used to predict the Arrhenius parameters ( E a and log A values) of four plastic explosives based on RDX and one high explosive based on PETN (Semtex). The slopes E a R −1 of Kissinger's equation were specified by means of non-isothermal differential thermal analysis (DTA) and evaluation of the measurement results by means of the Kissinger method. The role played by binders and plasticizers in thermal decomposition of nitramines was pointed out on the basis of relationship between the E a values obtained from VST and the E a R −1 values obtained from DTA, both for plastic explosives, eight nitramines, Composition B and PETN. The relationships between the E a R −1 values and thermostability threshold was specified for the given group of explosives. The relationship classify some of the studied plastic explosives as belonging to nitramines with steric hindrance in the molecule (CPX, TNAZ and HNIW). The relationship between E a R −1 values and drop energies, E dr, sharply differentiates between plastic explosives and individual nitramines. From the relationship between the E dr and D 2 values it was found that the increasing performance of the studied nitramines and plastic explosives is connected with the decrease in their impact sensitivity. Also specified are the approximate linear dependences between the peak temperatures of exothermic decomposition of all the explosives studied and their ignition temperatures, T ig, or critical temperatures, T c; these dependences were applied to prediction of T ig and T c of both the studied plastic explosives and some of the nitramines.