Energetic materials, structure characteristics

There have been a number of investigations involving the study of nitroolefins as useful intermediates in the synthesis of energetic materials. A characteristic of many of them is a large twist about the double bond. Interest in the structural characteristics that accompany the rotation motivates a discussion of details. As would be expected, the rotation out of the normal planar conformation is associated with spatial crowding. Rgure 14 illustrates some of the largest out-of-plane rotations that have been measured and, in one case, calculated for crowded ethylenes [25j. 

Most of the unique properties exhibited by polymers are a result of the quasi-unlimited number of spatial arrangements that long chains can assume [123], The knowledge of the energetic effects accompanying the changes from one configuration to another, in correlation with the structural characteristics of the chains, is paramount to interpret and predict the physical properties of polymeric materials [124],... 

One of the ways of specification of this mechanism can lie in study of relationships of the said sensitivity of energetic materials to their molecular structure [32], thermal reactivity [35,39,52,109-111], sensitivity to mechanic stimuli [32,109,112,113] and detonation characteristics [5,33,34,47]. As already stated, a thermal stimulus could be the basis of electric spark initiation [35,39,52,53],... 

Oyumi, Y. and Brill, T.B. (1986) Thermal Decomposition of Energetic Materials 11. Condensed Phase Structural Characteristics and High Rate Thermolysis of Di- and Trinitroaliphatic Carboxylic Acids and Carbonates Combustion and Flame 65, 103-111. 

From the present results it can be said that mechanical harm inflicted on energetic materials manifests itself in hot spots as chemical and physical changes. The physical changes are perhaps dependent on the melting, subliming characteristics, crystal habit and other properties of the material. They show up as holes in TATB but stringed structure in TNT. The explosive in the vicinity of hot spots becomes chemically... 

Although the thermodynamics of the products of multistage polymerization determine which structure will be the most stable, it is possible, and frequently necessary, to produce particle structures that appear nominally to be thermodynamically forbidden. This is achieved either by changing the surface characteristics of a polymer phase from those of the bulk material or by employing kinetic factors to produce and anchor energetically unfavored morphologies. Both types of methods are summarized below. 

In addition to structural (geometric) heterogeneity, characterized by different pore shapes and sizes, activated carbons like all porous solids may present surface energetic heterogeneity (SEH). This heterogeneity is mainly due to the presence of functional groups and strongly bound impurities on the surface of pores, whose characteristics depend on the type of row material used and the conditions of carbonization and activation processes,... 

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