Explosives, molecular structure

Power index is based on the study of relationship between explosive molecular structures and the work power. Power index method refers that the work power of an explosive is the sum of all composition functions. It puts forward power index n. The calculation of work capability/ability of an explosive using power index method is in Eq. 2.47. 

Highly energetic compounds with potential use in explosive devices must be characterized completely and safely, particularly as the explosive character may be linked directly to vibrational modes in the molecular structure, hence the application of computational methods to complement experimental observations. ANTA 5 has been the subject of various studies and, as an adjunct to one of these and to confirm the results of an inelastic neutron scattering experiment, an isolated molecule calculation was carried out using the 6-311G basis set <2005CPL(403)329>. 

Four nitrosamines, seven nitramines, three nitroesters and the explosives Semtex 10 and Composition B have been investigated by TGA. Linear dependence was confirmed between the position of the TGA onsets, as defined in the sense of Perkin-Elmer s TGA-7 standard program, and the samples weights. The slope of this dependence is closely related to the thermal reactivity and molecular structure. The intercept values of the dependence correlate with the autoignition temperatures and with the critical temperatures of the studied compounds, without any clear influence from molecular structure. Results show that Semtex 10 exhibits approximately the same thermostability as its active component pentaerythrityl tetranitrate (PETN, 274). Results also show that TGA data for Composition B do not correlate with analogous data for pure nitramines564. 

Perchlorates are characterized by a CIO4 fragment/anion in their molecular structures and are crystalline materials used in propellants and explosives.P i] qq g oxy-... 

Nitroguanidine (NQ) is a nitramine compound containing one N-NOj group in its molecular structure. In contrast to cyclic nitramines such as HMX and RDX, its density is low and its heat of explosion is also comparatively low. However, the Mg of its combustion products is low because of the high mass fraction of hydrogen contained within the molecule. Incorporating NQ particles into a double-base propellant forms a composite propellant termed a triple-base propellant, as used in guns. 

Hydroxy-terminated polyester (HTPS) is made from diethylene glycol and adipic acid, and hydroxy-terminated polyether (HTPE) is made from propylene glycol. Hydroxy-terminated polyacetylene (HTPA) is synthesized from butynediol and paraformaldehyde and is characterized by acetylenic triple bonds. The terminal OH groups of these polymers are cured with isophorone diisocyanate. Table 4.3 shows the chemical properties of typical polymers and prepolymers used in composite propellants and explosives.E4 All of these polymers are inert, but, with the exception of HTPB, contain relatively high oxygen contents in their molecular structures. 

Figure 4.5 shows the chemical processes and molecular structures of typical inert binders used in composite propellants and plastic-bonded explosives.Ph Polysulfides are characterized by sulfur atoms in their structures and produce H2O molecules during the polymerization process. These H2O molecules should be re-... 

Hydrocarbon polymers (HCP) are used not only as fuel components but also as binders of crystalline oxidizers and metal powders in the formulation of pyrolants, similar to composite propellants and plastic-bonded explosives. There are many types of HCP, the physicochemical properties of which are dependent on their molecular structures. The viscosity, molecular mass, and functionality of the poly-... 

Hydrophobic This group includes the nobel gases krypton and xenon, which bind to hydrophobic pockets in the protein. The main impediment to the use of these gases has been the technical challenge in derivatization under pressure, particularly since pressurized capillaries of glass or quartz are explosion hazards. A special device to make nobel gas derivatives has been described by Schiltz et al. (1994), and a commercial one is now being sold by Molecular Structure Corporation for use in cryocrystallography. 

Computational quantum chemistry has emerged in recent years as a viable tool for the elucidation of molecular structure and molecular properties, especially for the prediction of geometrical parameters, kinetics and thermodynamics of highly labile compounds such as nitrosomethanides. However, they are difficult objects for both experimental (high toxicity, redox lability, high reactivity, explosive character etc.) and computational studies, even with today s sophisticated techniques (e.g. NO compounds are often species with open-shell biradical character which requires the application of multi-configuration methods). 

Explosive Power vs Oxygen Balance, Correlation of. The relationship of oxygen balance to expl power as measured by ballistic mottathas been studied empirically. Starting from modified oxygen, balance developed for detonation velocity calculations, a numerical measure called the power index is derived which correlates closely the features of molecular structure with.the power values. Expl power has also been expressed as an additive function of details of molecular structure. This is the basis for a method whereby power values may be derived which agree with experimental results to about... 

To a chemist concerned Tyith the synthesis of new high-explosive compounds the ability to compute detonation properties (detonation pressure, energy, and velocity as well as product composition) from a given molecular structure and the known or estimated crystal density is a problem of the utmost importance. The calculated properties could be meaningful in the decision as to whether it is worth the effort to attempt a new and complex synthesis. One reason behind the recent development of detonation-properties programs for use on high-speed computers has been to supply this desired information. One such program, the ruby code,1 has recently been made available to a number of laboratories, the authors included. 

Correlation of Explosive Properties with Other Parameters "The Relationship between Performance and Constitution of Pure Organic Explosive Compounds is the subject of a review by Lothrop Handrick (Ref 1). Price (Ref 2) has reviewed the "Dependence of Damage Effects upon Detonation Parameters of Organic High Explosives , and Martin Yallop (Ref 3) have reported on "The Correlation of Explosive Power with Molecular Structure ... 

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