مجله تحقیق و توسعه مواد پرانرژی
سال پانزدهم شماره 2 (پیاپی 34، پاییز و زمستان 1398)

Aerogel is a unique nanoparticle that has grown dramatically in the world of chemistry over the past few decades. Aerogel features: Very low density, ultra-porous surface, sound and heat absorber, and super hydrophobic. Depending on the type of aerogels and their synthesis methods, different applications in military industries such as: Explosives, Rocket fuels, thermal insulation, sound insulation, energy insulation, and civilian, such as: batteries and capacitors, sensors, radio detectors, lasers and optics, engineering, electronics, and catalytic constructions. In this article, aerogels and their types, synthesis methods, their properties and some applications in military and civilian industries have been studied.

In this study, the recent developments in the synthesis of some azo- linked high- nitrogen energetic heterocycles such as tetrazole, triazole, imidazole, pyrazole, triazine, tetrazine and their salts will be investigated. These energetic compounds generally exhibit desirable properties and performance, which in some cases are superior to the conventional energetic materials such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), 2, 4, 6-trinitrotoluene (TNT) and 1,3,5-trinamino-2,4,6- trinitrobenzene (TATB).

Co-crystallization is an attractive molecular engineering approach for realizing improved energetic materials (explosives, propellants, and pyrotechnics). When two or more neutral species are combined to form a new structure, co-crystals are created with distinct solid-state properties. The performance criteria of energetic materials (explosive power, thermal stability, and physical sensitivity) are critically depended on some properties such as density and melting point. So, using co-crystallization could improve existing materials and even energetic compounds which were previously abandoned, due to having several disadvantages such as low density or high sensitivity. In this article, several most important efforts of scientists in the novel energetic molecular design field through co-crystallization technic are introduced. Also, reasons of the formation of a co-crystal are investigated from molecular structure point of view.

The use of compounds in powder form is common in many industries, including energetic materials. however, these compounds exposed to changes over time that lead to lumping and causes problems at use, transportation, and storage. The tendency to lumping that result from production, transport and storage can be attributed to interactions between particles and environmental factors such as temperature, humidity and mechanical conditions that affect the deformation of a powder. In this article, the mechanism of lumping, the factors affecting lumping and methods to prevent cake are discussed. In addition, anti-cake additives and the method of synthesis of some of them using the raw materials of azide, nitrile, halide, alcohol, amide, carboxylic acid and etc in the presence of various catalysts are Reviewed and their properties are described has been discussed.

Plastic Bonded Explosives with inert binder despite having good mechanical properties and low sensitivity, because of containing inert materials, have low energy level. So investigations for replacing inert binder system with energetic binder system and high exploding components in the making of these materials are performing. It seems using energetic polymers and materials like Cyclotetramethylene tetranitramine(HMX) in Plastic Bonded Explosives can overcome this problem. Investigations show using energetic polymers like Glycidyl Aide Polymer and PolyNIMMO give good explosion and mechanical properties to PBXs but it may cause to increasing these formoulations sensitivity to impact and friction. An important point in the making of PBXs is reaching to suitable energy level and also less sensitivity to impact and friction. In this article specifications of some energetic polymers, compataibility of this polymers with some common explosives and last investigations about using energetic polymers and plasticizers in the making of Plastic Bonded Explosives was reviewed.

Metal powders are combined due to high heat reaction with oxygen, improve the density of the propellant, decrease the pressure exponent (n) and Higher combustion heat, and as a result of higher ISP in propellant. Aluminum, magnesium and boron have found a wide application in propellant formulations. Boron, due to high oxidation heat and low atomic weight, is one of the best elements known. Unfortunately, it is very difficult to ignition due to its inherent reactivity and its surface covering with oxide. In compared, the magnesium is easily flammable and by covering a boron particle with magnesium, the boron combustion properties increase significantly. Boron-based propellant technology is the key to ramjet engines for aerodynamic rockets with supersonic speeds (M> 4-8), high height (H> 15-40 km), ultra-low height (H <100-300 m), and medium range (L> 100 km) Also, the main technology supports hybrid engines with drift force is adjustable.

The explosives, in manufacturing, transporting and using at military installations, caused to pollution of ground and subground waters, soils and sediments. Soil is posed as a relationship between water, weather and plants and animals existence of a zone. Therefore, soil health is a necessary matter. So, in order to suppression from environmental issues and human detriment, polluted soil improvement form these materials are required. This improvement can be done by physical, chemical and biological routes. In early decades, bio-improvement is more considered, due to environment friendly, health and safety. Bio-improvement processes if explosives are implemented by two routes: biological stimulus and biological amplification. In this paper, methods of green improvement for polluted soil refinement such as composting, utilizing of transgenic plant, microbes and etc. from common energetic materials such as TNT, RDX, HMX AND Cl-20 are investigated.