Nanocomposites: An Ideal Coating Material to Reduce the Sensitivity of Hydrazinium Nitroformate (HNF)

Abstract Hydrazinium nitroformate (HNF), an energetic and eco‐friendly oxidizer, was desensitized successfully by changing its crystal size and shape and by coating with a nanocomposite. During crystallization, various methods were tried out which include mechanical stirring, ultrasound and using crystal shape modifiers (CSMs). Experimental results showed that the multi‐pronged approach to control the shape and size of the crystals by a careful choice of CSMs and crystallization method worked well to counter the preferential axial crystals growth, thus shifting the long needles to near cubical shape. Among various coating agents, a hydroxy‐terminated poly butadiene (HTPB)‐based clay nanocomposite was found to be most effective for reducing the friction and impact sensitivity of HNF. A Scanning Electron Microscope (SEM) coupled with Energy Dispersive Spectroscopic (EDS) analysis was found to be a very reliable and most useful technique to assess the extent of coating on HNF so as to achieve a consistent figure of insensitivity. The coating material was stable as well as compatible with the HNF crystals as revealed by thermal analysis.