Sensitivity, energetic materials

The use of radioactive ionization sources in areas subject to explosion or fire is undesirable because of the potential for area contamination with radioactive material which could be disseminated in the event of an explosion or fire. With proper precautions, however, electrical ionizing systems can be safely and effectively utilized while processing electrostatically sensitive energetic materials. Ions are generated electrically by corona discharge... 

Precipitation of trinitrobenzene or other sensitive energetic materials in the energetics slurry handling and SILVER II system was identified as a concern during Demo II testing. Design changes identified in the final EDP and demonstrated in EDS II 12-kW tests appear to adequately prevent precipitation. 

How readily this sequence of events will occur for any given compound (i.e. its sensitivity) depends of course upon its molecular structure and composition, as well as its crystal properties and physical form. Achieving greater insight into molecular factors offers a route to designing new less-sensitive energetic materials understanding crystal and... 

Fig. 1.2 Subdivisions of sensitive energetic materials with some cxmunon examples...

From the perspective of sensitivity, the most sensitive energetic materials are primary explosives, less sensitive are secondary explosives, and very insensitive are tertiary explosives. Rigorous limits between these groups do not exist and new explosives are therefore related to the existing ones through a series of comparative experiments. Some authors define primary explosives as substances being more sensitive than PETN. 

Many attachments and special devices have been developed to extend and implement the applicability of the OM. One of these is a controlled atmosphere microscope dry-box which offers reproducible environmental control for applications involving toxic, air, or moisture sensitive ingredients, typical of many energetic materials (Ref 33)... 

This section will deal briefly with some aspects of expls safety peculiar to neutron activation analysis expts. We are concerned here with a) the possible effect of the ionizing radiation dose on the energetic material which will cause it to be more sensitive or hazardous to normal handling as an expl, and b) the potential direct expl hazards involved in the physical and mechanical transportation of samples to and horn the irradiation source and in a nuclear counting system... 

The frst step in the approach is to draft a test plan which will generate both the required technical data and the sensitivity of the reaction parameters. If large scale continuous processing of very energetic materials is considered,... 

We have synthesized two small scale batches (PA-DBX 1 and 2) of 2-3 g each and one intermediate scale batch (PA-DBX 3) of 8-10 g of DBX-1 from our NaNT. The procedure used to synthesize DBX-1 was based on literature methods.[5,6] For each batch, sensitivity tests, thermal stability by differential scanning calorimetry (DSC), and performance tests were performed and compared to the standard DBX-1 that was obtained from PSEMC (Pacific Scientific Energetic Materials Company, inventors of DBX-1). 

CAUTION Sodium nitrotetrazolate dihydrate is an energetic material with sensitivity to various stimuli. Particular care should be taken to not excessively dry the material, as anhydrous NaNT is considerably more sensitive than the dihydrate. While we encountered no issues in the handling of this material, proper protective measures (face shield, ear protection, body armor, Kevlar gloves, and earthened equipment) should be used at all times. 

Syntheses of 5 energetic aliphatic azido compounds are described caution is necessary in handling these because of their impact-sensitivity [1], A later symposium on energetic materials, here meaning explosives and popellants, is reported [2], Individual compounds are ... 

The weakest bonds in an explosive will often determine its sensitivity to impact and such bonds are usually present in the explosophoric groups. Steric and electronic factors also play an important role. Unsurprisingly, factors which increase explosive performance usually have a detrimental effect on stability and sensitivity, and so a compromise must be made. As the database of energetic materials and their properties is ever increasing this task becomes... 

The effect which amino functionality has on the thermal and impact sensitivity of polyni-troarylenes (Section 4.8.1.4) makes amination by VNS a method with much future potential for energetic materials synthesis. Other carbon, nitrogen, oxygen and sulfur nucleophiles can displace aromatic hydrogen examples with 1,3-dinitrobenzene and 1,3,5-trinitrobenzene are extensive. 

Li and co-workers recognised the potential of cyclic IV-nitroureas as energetic materials and reported the synthesis of 2,4,6,8-tetranitro-2,4,6,8-tetraazabicyclo[3.3.0]octane-3-one (109) (K-55) from the nitration of 2,4,6,8-tetraazabicyclo[3.3.0]octane-3-one dihydrochloride (108) with absolute nitric acid in acetic anhydride at room temperature the latter obtained from the condensation of lV,lVL(iiformyl-4,5-dihydroxyimidazolidine (107) with urea in aqueous hydrochloric acid. Pagoria and co-workers " " reported the synthesis of 2,4,6-trinitro-2,4,6,8-tetraazabicyclo[3.3.0]octane-3-one (110) (HK-55) in 72% yield from the nitration of (108) with 90 % nitric acid in acetic anhydride at subambient temperature (Table 5.3). HK-55 has a relatively high density (1.905 g/cm ) coupled with a low sensitivity to shock. 

Analyses of the structures and properties of a large number of energetic materials reveal that a combination of amino and nitro groups in a molecule often leads to better thermal stability, lower sensitivity to shock and impact, and increased explosive performance because of an increase in crystal density. Such observations are attributed to both intermolecular and intramolecular hydrogen bonding interactions between adjacent amino and nitro groups. Some modern triazole-based explosives have been designed and synthesized with this in mind. 

Propellants, explosives, and pyrolants are all energetic materials designed to have maximum energy density within a limited domain of mechanical sensitivities, manufacturing requirements, physical properties, and combustion characteristics. 

In general, the burning rate of an energetic material is seen to increase linearly with increasing pressure in an hr p versus hr rplot represented by Eq. (3.68) at constant initial temperature Tq. Thus, the pressure sensitivity of burning rate at a constant initial temperature, n, is defined by... 

The temperature sensitivity of the burning rate defined in Eq. (3.72) is a parameter of considerable relevance in energetic materials. 

Equation (3.89) is the expression for the temperature sensitivity of an energetic material based on the analysis of a one-dimensional, one-step reaction in the combustion wave. 

Slurry explosives consist of saturated aqueous solutions of ammonium nitrate with sensitizing additives.[i-3] Nitrates such as monomethylamine nitrate, ethylene glycol mononitrate, or ethanolamine mononitrate are used as sensitizers. Aluminum powder is also added as an energetic material. Table 4.15 shows a typical chemical composition of a slurry explosive. It is important that so-called micro-bubbles are present within the explosives in order to facilitate the initial detonation and the ensuing detonation wave. These micro-bubbles are made of glass or polymeric materials. 

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