Characterization of Explosives & Precursors
Project R1-A1 seeks to determine physical properties, synthesis, and destruction mechanisms of improvised explosives, often called homemade explosives (HMEs). The overall objectives are that detection, handling, and transport of these materials by the Homeland Security Enterprise (HSE) be as safe as possible while obstructing the manufacturing of HME by terrorists.
New materials require characterization; in the case of explosives, complete characterization is a matter of safety as well as performance. HMEs are not exactly new, many having been reported in the late 1800s. However, their “routine” handling and resulting accidents by those involved in the HSE requires a thorough understanding of their properties. To detect, destroy, handle safely, or prevent the synthesis of HMEs, complete understanding of the following aspects is required:
- How an HME is formed and what accelerates or retards that formation;
- How it decomposes and what accelerates or retards that decomposition;
- How it crystallizes;
- What is its vapor pressure and what is its headspace signature;
- What is its density;
- What is its sensitivity to accidental ignition as well as purposeful ignition; and
- What is its performance under shock and fire conditions?
Given the large scale of this mission, we have chosen areas considered most urgent or reachable by our present experience and instrument capabilities. We have examined triacetone triperoxide (TATP) and erythritol tetranitrate (ETN) in detail. Presently, we are examining hexamethylene triperoxide diamine (HMTD) and fuel/oxidizer (FOX) mixtures.
Previous research has probed aspects of the formation and decomposition of HMTD. Water greatly enhances its decomposition. Ambient vapor signatures of HMTD appear to be primarily decomposition products; this aspect will be further examined from safety and detectability perspectives. Gentle destruction methods and methods of thwarting illicit synthesis will be sought and vapor detection schemes studied.
There is little definitive information about the characteristics of FOX mixtures that make them explosive. Instead, there is speculation in terms of what “works” and what “ought to work”. Our research in this second area has two goals:
- To allow the HSE to narrow or widen the list of threat oxidizers; and
- To collect and match sufficient small-scale data (thermal stability, gas production, friction sensitivity, etc.) to large-scale performance (detonation or explosion, see project R1-B.1) so that small-scale data will achieve greater predictive value.
The predictive value of the small-scale data is achieved so that the range of FOX mixtures which can be used as explosives can be bounded, not only in terms of what materials, but also in terms of necessary concentrations. Addressing burn and detonation characteristics will continue.
Studies suggest that thwarting the synthesis of HMTD will be challenging. Further mechanistic studies are underway in order to devise the best approach to this problem.Phase 2 Year 2 Annual Report
Faculty and Staff Currently Involved in Project
Students Currently Involved in Project
- Maria Donnelly
- Matt Porter
- Austin Brown
- Devon Swanson
- Lindsay McLennan
- Jon Canino
- Kevin Colizza
- Stephanie Rayome