ORIGINAL PAPER Micro structural investigations on TNT and PETN incorporated silica xerogels S. V. Ingale • P. U. Sastry • A. K. Patra • R. Tewari • P. B. Wagh • Satish C. Gupta Received: 29 December 2009 / Accepted: 1 March 2010 / Published online: 2 April 2010 Ó Springer Science+Business Media, LLC 2010 Abstract Silica xerogels incorporated with trinitrotolu- ene (TNT) and pentaerythritoltetranitrate (PETN) were synthesized using sol–gel method. Tetramethoxysilane was used as precursor for silica. TNT and PETN content in the resulted explosive/silica xerogel was varied ranging from 50 to 90%. Infra red spectra showed that explosives were retained in the silica xerogel matrix. Transmission electron microscopy (TEM) reveal that explosives particles were uniformly distributed in xerogel matrix and the size of the PETN and TNT particles are in the range 15–18 nm. Small angle x-ray scattering showed that the sizes of the pores in the silica matrix are in the range 25–13 nm. The particles of TNT and PETN occupy the pores in the matrix resulting in gradual reduction of pore-size affecting the surface characteristics of the pore-matrix interface. Understanding of the structure of aggregates of small particles thus pro- duced could be useful to explain the properties shown by the fine explosives. Our study suggests that particle size of explosives in the nanometer range can be achieved using the sol–gel method. Keywords Xerogel  Explosives  SAXS  TEM 1 Introduction The initiation and detonation properties of explosives depend on their micro structure. For instance, the secondary explo- sives developed with reduced particle size tend to be more insensitive for mechanical stimuli and may release energy with faster rate on initiation [1]. This property of fine explo- sives is useful for development of electric bridge wire (EBW) detonators and low vulnerable (LOVA) propellants [2, 3]. Therefore, preparation and investigations of fine explosives gained significant importance. Methods of preparing fine explosives mainly involve milling [4], crystallization out of solution by rapid cooling or using non solvent [4], conven- tional crystallization coupled with ultrasonically induced nucleation [5], rapid expansion of supercritical solvent and gas-anti solvent method [6], and sol–gel technique [7]. Understanding of the structure of aggregates of small particles thus produced could be useful to explain the properties shown by the fine explosives. In this work, we have explored the feasibility of silica xerogel as a host to the TNT and PETN explosives that can confine the particle size of these explosives to the nano meter range. The particle sizes of explosives and the pore morphology of resulted xerogel are characterized by transmission electron micro- scope (TEM) and small angle x-ray scattering (SAXS). 2 Experimental 2.1 Preparation of silica xerogels incorporated with TNT and PETN TNT and PETN incorporated silica xerogels are prepared using solution crystallization sol gel process [8]. Explosive (TNT/PETN) was dissolved in acetone and to this solution S. V. Ingale (&)  P. B. Wagh  S. C. Gupta Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India e-mail: svingale@barc.gov.in P. U. Sastry  A. K. Patra Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India R. Tewari Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400085, India 123 J Sol-Gel Sci Technol (2010) 54:238–242 DOI 10.1007/s10971-010-2188-7