Equations of State and High-Pressure Phases of Explosives

  • Suhithi M. Peiris
  • Jared C. Gump
Part of the Shock Wave and High Pressure Phenomena book series (SHOCKWAVE)

Energetic materials, being the collective name for explosives, propellants, pyrotechnics, and other flash-bang materials, span a wide range of composite chemical formulations. Most militarily used energetics are solids composed of particles of the pure energetic material held together by a binder. Commonly used binders include various oils, waxes, and polymers or plasticizers, and the composite is melt cast, cured, or pressed to achieve the necessary mechanical properties (gels, putties, sheets, solid blocks, etc.) of the final energetic material. Mining, demolition, and other industries use liquid energetics that are similarly composed of an actual energetic material or oxidizer together with a fuel, that is to be mixed and poured for detonation. Pure energetic materials that are commonly used are nitroglycerine, ammonium nitrate, ammonium or sodium perchlorate, trinitrotoluene (TNT), HMX, RDX, and TATB. All of them are molecular materials or molecular ions that when initiated or insulted undergoes rapid decomposition with excessive liberation of heat resulting in the formation of stable final products. When the final products are gases, and they are rapidly produced, the sudden pressure increase creates a shock wave. When decomposition is so rapid that the reaction moves through the explosive faster than the speed of sound in the unreacted explosive, the material is said to detonate. Typically, energetic materials that undergo detonation are known as high explosives (HEs) and energetic materials that burn rapidly or deflagrate are known as low explosives and/or propellants.

The singular character of energetic molecules is that they are very easily initiated, even just by friction caused when twisting of the container cap to open the container. That is, these materials are so sensitive to perturbation that their reaction or decomposition is easily started. This certainly implies that the molecule is inherently unstable or strained at ambient pressure and temperature, or that its heat of formation is very low in comparison to the formation of other phases or products from the same chemical composition. In the case of high explosives, positive values for the heat of formation is not unknown, perhaps explaining the multiple meta-stable crystalline structures or polymorphs discovered at ambient pressure and temperature. Consequently, the phase diagrams of HEs and their high pressure, high-temperature phase transitions are often very complex.


Bulk Modulus Ambient Pressure Unit Cell Volume Pressure Medium Ammonium Perchlorate 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  • Suhithi M. Peiris
    • Jared C. Gump
      • 1
    1. 1.Indian Head DivisionNaval Surface Warfare CenterIndian HeadUSA

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