فصلنامه مواد پر انرژی
سال یازدهم شماره 1 (پیاپی 29، بهار 1395)

For hydrazine producing with concentration more than 64 wt%, remaining amount of water in hydrazine Hydrate, could not be removed easily to produce hydrazine with concentration more than 64wt%. In this work, Butanol, an aliphatic alcohol with four carbone atoms, was used as a solvent in liquid - liquid extraction of hydrazine. The binodal curve and the experimental tie lines for the ternary {water (1) – hydrazine (2) – butanol (3)} system were determined by cloud point method using the refractive index criteria at the temperatures of 15.2, 25.2 and 40.2 C, in atmospheric pressure. The distribution coefficient of Hydrazine (D) and its separation factor (S) were determined equal to 0.0425-0.3628 and 0.2768- 1.5179, in the usage concentration and temperature ranges, respectively. Afterword the experimental tie lines were correlated by the Non-Random Two-liquid model (NRTL) and the Universal Quasi Chemical model (UNIQUAC) with Root Mean Square Deviation (RMSD) equal to 0.0227 and 0.0495, respectively. In addition, the sodium hydroxide addition effect was studied on equilibrium behaviour of the system at 25.2 C. Addition of 10 wt% NaOH causes an increase of 13.16 % in the average distribution coefficient of hydrazine as well as 96.26% in the average separation factor.

One of the characteristics of solid organic compounds and especially organic explosives is thermal behavior and kinetic of thermal decomposition. The activation energy, Arrhenius constant and model of solid state reaction as kinetic triplet can be obtained by study thermal decomposition kinetic in a solid state reaction. In the present work, the non-isothermal differential thermal analysis (DTA) was used to study of kinetic triplet of thermal decomposition of Acfol explosive with composition of 5% wax and 95% HMX explosive. The DTA thermograms of Acfol were investigated in heating rates of 2, 4, 6 and 8 ° C per minute in an argon atmosphere. The model-free methods of Kissinger-Akahira-Sunose (KAS) and Ozawa-Flynn-Wall (OFW) were used for calculation of activation energy. The average of activation energy was obtained 214.17±25.22 and 233.45±4.63 kJ/mol by KAS and OFW methods respectively in the range of conversion fraction (&alpha) of 0.1-0.9. The kinetic triplet of activation energy, Ea, frequency factor (A) and the reaction model (functions of f(&alpha) and g(&alpha)) were also investigated using model-dependent methods. The obtained results were showed the A3 model with functions integral of [-ln(1-a)]1/3 and differential of 3(1-a)[-ln(1-a)]2/3, activation energy of 226-241 kJ/mol and logA of 13.5-15.8 1/s for thermal decomposition of Acfol explosive.

Thermal paper as a pyrotechnic source of thermal batteries is typically including combinations of barium chromate, zirconium and mineral fibers. For the deposition of barium chromate and zirconium microparticles on thermal paper, these should be dispersing in solution. In this study, dispersion of these particles in aqueous medium by using sodium dodecyl sulfate (SDS), Triton X-114, carboxymethyl cellulose (CMC), cetyltrimethylammonium bromide (CTAB), cetylpyridinium chloride (CPC) surfactants and using of UV-Visible spectroscopy were investigated. In this regard to determine the optimal condition, the effect of parameters of milling time, mixing time and temperature has been studied. First the medium pH must be adjusted lower that the isoelectric point (pH=6.5-6.8) because the particle surface charges opposite to the surfactant charge. The results showed that in comparison with the other surfactants, CMC is more effective for the both particle. Condition Optimization for 0.005 M of barium chromate and 0.022 M of zirconium indicated that the milling times of 120 and 180 minutes, the stirring times of 180 and 120 minutes and the temperatures of 70 and 80 °C were optimize respectively.

The reversibility of the Diels-Alder reaction can be used advantageously in polyurethane materials to endow them with recyclable, thermally reversible properties and self-healing ability to expand their application range. In this paper, linear and crosslink polyurethanes based on HTPB, which exhibit thermal reversibility through Diels-Alder and retro Diels-Alder reactions, were prepared and characterized from reaction of bismaleimide and furan terminated polybutadiene. Also tetrafuran cross linker is synthesized and characterized by FT-IR and NMR for preparation of Diels-Alder network. Reversibility of Diels-Alder reaction was investigated through heating and cooling cycle by using differential scanning calorimetry (DSC). The results have shown that the retro Diels-Alder reaction is occurred at 150°C. Evaluation of healability of prepared polyurethane was done by cutting of polymer and recovering of its initial shape after reheating at 150°C.

In this study, the method of molecular dynamics simulation is performed to investigate the effect of voids on shockwave propagation in solid argon. The case study is a non-interactive solid modeled by Buckingham potential function. The shockwave is generated using the motion of a piston with different velocities in the solid that leads to increase the temperature after its propagation. The resulted shockwave velocity is in good agreement with the experimental data and the Hugoniot curve. It is also found that voids with different geometries and sizes lead to have the same temperature increment with less initiation piston velocity (less threshold initiation).

Aerosolization of tear agents using pyrotechnic formulation containing fuel, oxidant, coolant and binder was investigated. In this study, various tablets including different amounts of potassium chlorate (as oxidizer), lactose or sucrose (as fuel), silica and aluminium oxide (as coolant), nitrocellulose, castor oil and ethyl acetate mixture (as binding system) together with terphtalic acid (as effective agent) were prepared. The optimized formulation was chosen regarding to the various parameters such as time, temperature, and ignition procedure and then CR was used as tear agent in the optimized formulation. Gas chromatography (GC) and thermal analysis (TG/DTA) techniques were used to determine the quality of aerosolization. The results showed that the time of ignition and efficiency of aerosol production by pyrotechnic formulation containing lactose is higher than using sucrose as fuel. TG thermal analysis showed that mass reduction in the formulations with each of the two types of fuel in temperature range of 125-180 ºC was related to evaporation of CR. Finally, CR aerosolization with the efficiency of 45% and 85% were obtained with sucrose and lactose as fuel, respectively.

Mechanical properties and burning rate are very important parameters for solid propellants. In this work, the effects of quality and quantity of stabilizers as AkarditeII, 2-NDPA and CentraliteI on the Mechanical properties and burning rate of double-based is investigated. The results showed that, by CentraliteI increased mechanical properties of propellant and for AkarditeII and 2-NDPA stabilizers mechanical properties was lower than CentraliteI. Increasing the amount of AkarditeII decreased burning rate and increasing the amount 2-NDPA increased burning rate.