Nanocrystalline trinitrotoluene (TNT) using sol–gel process

The secondary explosives with superfine particle size have many applications, for example, in synthesizing low vulnerable propellants and explosive bridge wire detonators. We have developed a method for preparation of nanocrystalline trinitrotoluene (TNT) in the silica gel matrix using sol–gel process. The TNT/silica xerogels were prepared containing up to 90% TNT and 10% silica. An exothermic peak at around 280 °C in DTA curve of xerogel associated with weight loss due to TNT decomposition as indicated in TGA curve confirmed the presence of TNT in the xerogel. Infrared spectrum of the xerogel showed peaks at 1550 and 1350 cm−1 assigned to C–NO2 bond in TNT and peaks at 1100 and 450 cm−1 associated with Si–O bonding in silica. Small angle X-ray scattering measurements revealed that TNT entered the pores of the silica matrix resulting in reduction of average pore size of the gel matrix. Dynamic light scattering measurements indicated an average particle size of 280 to 443 nm for silica clusters. XRD analysis showed the crystalline nature of TNT with an average crystallite grain size of around 41 nm. Transmission electron microscopy revealed that nanocrystalline TNT particles with sizes ranging from 5 nm to 45 nm were dispersed in silica matrix.