Energetic materials crystalline

Hare D E, Franken J and DIott D D 1995 A new method for studying picosecond dynamics of shocked solids application to crystalline energetic materials Chem. Phys. Lett. 244 224... 

Since numerous kinds of energetic materials are used as propellants and explosives, it is not possible to present an entire overview of the combustion processes of these materials. In this book, the combustion processes of typical energetic crystalline and polymeri c materials and ofvarioustypes of propellants are presented so as to provide an informative, generalized approach to understanding their combustion mechanisms. 

In contrast to other crystaUine nitrates, pentaerythrol tetranitrate (PETN C Hg(0N02)4) is a crystalline nitrate ester similar to NG and NC. Though PETN is one of the most powerful energetic materials used in explosives, no excess oxidizer fragments are formed when it decomposes. Thus, PETN is not used as an oxidizer of propellants. 

The physicochemical properties of explosives are fundamentally equivalent to those of propellants. Explosives are also made of energetic materials such as nitropolymers and composite materials composed of crystalline particles and polymeric materials. TNT, RDX, and HMX are typical energetic crystalline materials used as explosives. Furthermore, when ammonium nitrate (AN) particles are mixed with an oil, an energetic explosive named ANFO (ammonium nitrate fuel oil) is formed. AN with water is also an explosive, named slurry explosive, used in industrial and civil engineering. A difference between the materials used as explosives and propellants is not readily evident. Propellants can be detonated when they are subjected to excess heat energy or mechanical shock. Explosives can be deflagrated steadily without a detonation wave when they are gently heated without mechanical shock. 

Crystalline particles that produce gaseous oxidizer fragments are used as oxidizer components and hydrocarbon polymers that produce gaseous fuel fragments are used as fuel components. Mixtures of these crystalline particles and hydrocarbon polymers form energetic materials that are termed composite propellants . The oxidizer and fuel components produced at the burning surface of each component mix together to form a stoichiometrically balanced reactive gas in the gas phase. 

Manual search identification data for various crystalline energetic materials, drawn from the above file and other sources are presented in Tables 1 (inorganic) and 2 (organic). The strongest reflections (the most intense on film or the highest in amplitude on a recorder chart) of the... 

The atomistic models presented in the previous sections can also be applied to the case of ionic energetic materials. Sorescu and Thompson have illustrated this for the case of crystalline ammonium dinitramide (ADN)... 

The high explosive octahydro-l,3,5,7-tetranitro-l,3,5,7-tetrazocine (HMX, Fig. 1) is the energetic material in a number of high performance military explosive and propellant formulations [3], HMX exhibits three crystal polymorphs at ambient pressure denoted J3- [4,5], a- [6], and <5-FlMX [7] and listed in terms of stability with increasing temperature. At temperature T 550 K the crystalline structure become unstable and HMX begins to melt. The liquid phase of HMX is very unstable and therefore no direct measurements of... 

So far we have discussed initiation with a single orientation of the unshocked crystalline solid. It is known however that initiation depends on crystal orientation in energetic materials such as PETN, and this orientation dependence has been exploited to gain insight into the steps leading to initiation. 

This term describes improved properties of energetic materials. In the 1990s it was shown that with careful recrystallization techniques the sensitivity RDX can be reduced on a crystalline level. Nowadays, reduced sensitivity variants of RDX, assigned as RS-RDX or l-RDX (for insensitive), are provided by different manufacturer and tested, particularly in plastic bonded explosives PBXfor Insensitive Munitions IM. Besides, RS-variants of HMX and other high explosives, and characterization and quality assessment techniques for Reduced Sensitivity are in the scope of actual research. 

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