Effect of particle size and shape of NTO on micromeritic characteristics and its explosive formulations

• Prepared spherical NTO of specific particle size viz., 150,100,25,15, 10 & < 5 μm
• Micromeritic properties of NTO were determined and correlated with size & shape.
• Bimodal mixture was identified based on packability & flowability parameters.
• Paste explosive formulations were made and their flow behavior studied.
• Spherical NTO brought down the viscosity by about 75% compared with non-spherical.

Particles with spherical shape and specific size distribution are major considerations in achieving high performance, solid loading and mix fluidity in processing of energetic materials for high explosive/rocket propellant applications. Spherical 3-Nitro-1, 2, 4-triazol-5-one (NTO) of specific particle size distribution (PSD) was prepared by a proprietary process and the powders were characterized by X-ray powder diffraction, thermal and spectral methods. Present study explores the spherical-NTO of specific particle size D (4, 3) of 150, 100, 25, 15, 10, and less than 5 μm and their bi/trimodal mixtures for their micromeritic properties. From the packability and flowability constants, bimodal mixture of coarse (150 μm) to fine (25 μm) ratio of 70:30 is found to be optimum for processing in explosive formulations. Paste explosive formulations were made based on identified bimodal mixture and their flow behavior studied by viscosity studies. The study inferred that spherical particles of NTO bring down the viscosity by about 75% for the same explosive content to binder ratio in comparison with non-spherical-NTO. Porosity data also supports the same for improvement in explosive loading by 10% by the usage of spherical-NTO over non-spherical particles for the given explosive to binder ratio.

Micromeritic characterization of 3-Nitro-1, 2, 4-triazol-5-one (NTO) powder is very much essential before it is realized in the explosive formulations. Effects of particle size and shape on various micromeritic properties of NTO powders were studied. A bimodal distribution comprising of 150 and 25 μm spherical NTO particles in 70:30 ratio has been identified by considering density and flowability. Paste explosive formulations were made with the bimodal mixture and viscosity studies ensured the improvement in mix-fluidity of these compositions based on spherical-NTO compared with non-spherical-NTO. Porosity data also supports the same improvement in explosive loading by 10% by the usage of spherical-NTO over non-spherical one, for the given explosive to binder ratio. Overall the study concludes that the spherical NTO powders are vital in realizing the HE/propellant formulations with increased explosive content that can lead to enhanced performance.Figure optionsDownload as PowerPoint slide