Effect of Natural Ageing on the Safety Parameters and Performance of TNT-based Melt Cast RDX/TNT Compositions

2,4,6-Trinitrotoluene (TNT) based melt cast RDX/TNT compositions stockpiled for a period of time were exposed under natural environmental conditions, with humidity and temperature for storage in the range of 40-95% RH and 4-47 °C, respectively. The composition, chemical, thermal and mechanical properties of the RDX/TNT compositions before and after ageing were studied by high performance liquid chromatography, Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry and a universal test machine, respectively. In addition, the safety, mechanical sensitivities, detonation velocity and blast parameters were also investigated through vacuum stability tests (VST), a BAM fall hammer apparatus, a BAM friction tester and a piezoelectric accelerator, respectively. The results showed that after ageing, the colour of the composition had become dark but there was no variation in the RDX and TNT content by high performance liquid chromatography (HPLC). The VST results showed that the volume of evolved gas was almost the same and less than 2 mL/g, indicating chemical stability. The results obtained from different analytical techniques demonstrated that there was no significant variation in the chemical, thermal and mechanical properties for the aged samples as compared to the fresh composition. The change in mechanical sensitivity is related to the components and the ageing mode. The detonation velocity and detonation pressure were found to be similar to those of the freshly prepared composition and consistent with the data obtained from overall natural ageing. The results of blast studies revealed that there was either a similar or slight variation in the blast peak over pressure and impulse for RDX/TNT compositions at different locations before and after ageing under natural environmental conditions.