جستجوی مقالات مرتبط با کلیدواژه « ایمنی » در نشریات گروه « مواد و متالورژی »

Surface coating is the most common method to reduce the sensitivity of energetic materials. The efficiency of this technique depends on the preparation method and the coating agents. This process is carried out through different methods. In order to reduce the sensitivity of HMX particles, waxes are conventionally used, which leads to decrease in HMX energy content. In this research, using three energetic compounds NC, DINA and TNT, the solvent/anti-solvent method was used for HMX coating. The scanning electron microscopy (SEM) was utilized to investigate the morphology. The results showed that uniform samples with optimal coverage are composed of coating agents. The Fourier-transform infrared (FT-IR) spectra confirmed the surface interaction between the HMX and coating agents. The thermal behavior of the coated samples was investigated by simultaneous thermogravimetric and differential scanning calorimetry analysis (TG-DSC). Results showed that while maintaining the thermal stability of coated HMX in respect to pure HMX, the heat of reaction from 1569.29 J/g for pure HMX increased to 1612.88, 1707.01, and 1690.38 J/g equivalent to 2.8%, 8.8% and 7.7% for coated samples with NC, DINA and TNT, respectively. Additionally, in the case of the HMX/TNT, the impact sensitivity of the 1 kg sample is reduced compared to the pure HMX, and for HMX/NC and HMX/DINA, no significant change was observed.

In this study, the synthesis, physicochemical properties and energetic performance of fused heterocycle based energetic materials with two or more rings are investigated. These compounds have been considered with a coplanar polycyclic structure, higher heats of formation (HOF) and ring-strain energy stored in the molecules. Good energetic performance, high thermal stability and low sensitivity toward destructive mechanical stimuli increase the safety of the synthesis, transfer, and storage of high- density energetic compounds. These properties make fused heterocyclic compounds a suitable alternative to conventional high-energetic materials for military and civilian applications Among the compounds studied, some of them have explosive performance comparable or higher than conventional explosives such as TNT, HMX, RDX or CL-20 and lower sensitivity to external stimuli. They are suitable candidate for replacement of conventional explosives. Because of their high specific impalse, some of them are suitable for use in high-performance propellant formulations. Also, the difference between melting point and decomposition temperature makes these fused heterocycles suitable as melt cast explosive.

the most part of the propellants,containig the oxidant and ammonium perchlorate is the most applicable oxidizer in composite solid propellants. Therefore, its thermal decomposition and safety properties have been a great effect on the propellants properties. The using of polymeric additives is one of the proper methods for improving the thermal and immunological properties of ammonium perchlorate. The types of additive are usually selected based on the applicable purpose. This paper reviews, the effects of polymeric additives to improve the sensitivity, the increase of thermal and chemical stability, and also the prevention of ammonium perchlorate particle agglomeration.

In addition to performance requirements, safety aspects for production, transportation and storage are very important for explosives because involuntary instantaneous explosion can causes irreparable financial losses and casualties. Ability of explosives for response to the stimuli such as impact, friction, shock wave, flame and heat is called sensitivity and is a key factor in determining the practical application of an explosive material. For decreasing of the sensitivity of explosives with maintained efficiency, it is necessary to use desensitizer. For this purpose, waxes, polymers, or a mixture of waxes and polymers can be used. In this research, industrial wax parameters in explosives such as melting point, congealing point, softening point, insoluble organic matterials, percentage of exudation, acidity, alkalinity, flash point,needle penetration, oil content and Differential Scanning Calorimetry (DSC) for three wax samples were determined by the credible standards. Finally, the results of parameters were analyzed.