مجله تحقیق و توسعه مواد پرانرژی
سال پنجم شماره 1 (پیاپی 8، بهار و تابستان 1388)

Boosters play an important role in the completion of fire explosion trains. One of the important and appropriate compositions used as a booster is CH-6 plastic bonded explosive (PBX) that has special application in boosters and underwater fuses. In this research, a suitable method is used for production of CH-6 composition that is compatible with industrial processes. Also, the effect of all parameters on the product quality, such as type of solvent, proportion of solvent to binder, temperature, rate of agitation, the size distribution of RDX particles and the amount of suspending agent, has been evaluated.

High reactivity of Azido group and the interest of energetic materials research centers in azido polymers in recent years due to energy increase and high generation of gas have led to the investigation and production of Azidodeoxycellulose. This compound is made up of nitrocellulose using an easy method and a new catalyst and has propellant application. In this article, methods of preparing nitrocellulose containing less than 10% nitrogen as intermediate (I) and Azidodeoxycellulos(II)have been discussed. The data related to the presence of azido group, the enhancement of nitrogen percentage confirmed by IR spectroscopy and elemental analysis. Heat of explosion, the volume of gas produced, and the thermal decomposition behavior of the product have also been studied.

Sol-gel chemistry is an approach to creating new energetic materials at the nanometer scale. Sol-gel approach to energetic materials offers the possibility of precisely controlling the composition, density, morphology and particle size of the target material at the nanometer scale. These are important variables for both safety and performance considerations. Such variables are difficult to achieve by conventional techniques.The fine control of these parameters allows the chemist the convenience of making energetic materials with tailored properties. Sol-gel is a method for creating stable energetic materials, so ambient temperature gelation and low-temperature drying schemes prevent the degradation of the energetic molecules and the water-like viscosity of the sol before gelation allows easy casting to near net shapes, which is preferred over the hazardous machining alternative. The aim of this study is to explain this method and its application in production of energetic materials. The nature of the process and the structure of the obtained products have also been discussed. At the end, the drying methods of the products together with the nature of this process have been presented.

Solid propellant can be deteriorated gradually while they are stored. This phenomenon usually occurs via an exothermic reaction called aging. This spontaneous reaction may release such an enormous heat causing the combustion of the propellant in its chamber. Therefore, it is necessary to achieve a method to characterize the propellant during its shelf life and to estimate the safe service time of these sensitive chemical materials, so that we can use the stored propellants safely. In this paper, we introduce methods which measure changes and deteriorations during shelf life in addition to estimating the expiration time of propellants. Despite the importance of this subject in military services, there is no comprehensive report on how the aging characterizations can be determined.

Nitroguanidine is an important constituent in certain explosive compositions particularly in propellants and for some of these compositions it is desirable to be able to manufacture nitroguanidine of very small particle size and a high bulk density and also in a form in which the crystals have better flowing and handing properties. The crystallization of nitroguanidine has been studied for many years and it is known that it is possible to prepare high bulk density nitroguanidine (HBNQ). HBNQ has been prepared in organic and aqueous solvents or combination of these solvents. Organic solvents are volatile, flammable and toxic, thus scaling up processes based on these solvents is difficult and uneconomical. However, aqueous solvent dont have these problems. In this research project, we used a process through which crystals of nitroguanidine were produced in a relatively spherical form and with a high bulk density. Methylcellulose and poly(vinyl alcohol) were used as additives(crystal habit modifier) and the effects of these additives and other parameters such as cooling rate, nitroguanidine concentration, stirring on bulk density, and crystal size distribution were studied.

In this paper, a powerful explosive system has been introduced where in porous silicon, as host matrix, is acceptor of different oxidizers. To produce porous silicon and prepare the surface, an electro-chemical etching was presented and then to prepare the related composites,the obtained product was processed. In this process, silicon single-crystal wafer as anode is electrochemically oxidized to form the porous silicon. The oxidation process depends on the parameters such as resistance, the electrolyte composition, crystallography orientation, temperature and current density. In during of the reaction, the system in proximity of HF is converted to and: Si + 2H+ + 6HF SiF62- + 2H2 + 4H+In the next stage, the produced pores by particular ways are filled with oxidizer agents that will change obtained product explosion properties depending on the filler type. In these cases, nitrate and perchlorate salts are usually used as oxidizer constituents. The obtained products have favorite mechanical stability, combust in normal and controllable ways and have long- time life.The performance energy and the obtained reaction rate are predictable and repeatable.The maximum energy release is 28 KJ/gr for this explosion and combustion temperature range was between 2900 K and 4100 K.

Expanding foam for controlling and reducing explosive blast have been used to reduce the harmful effect of shock wave when neutralization of explosives in public area and chemical warfare is to be performed. Recently, usage of expanding foam to reduce harmful effect of shock wave in the mine and petroleum site are developed. The reduction of blast noise by foam has also been studied. The major parts of this type of foam are aqueous. Some solid foams based on polymer have also been proposed, absorbing the shock wave and distributing the weight of persons or vehicles on the surface of sheet plat foamed to afford the possibility of safe passage through the land mine. In this contribution, the application and formulation of different type of foams to control and reduce the explosive blast are investigated.