JOURNAL OF ENERGETIC MATERIALS
Year:2019 | Volume:14 | Issue:1 (41)|Papers Count:6

In this research a new type of magnetic Pb(II) and Cr(VI) ion-imprinted polymers were synthesized using Fe3O4@SiO2 magnetic particles as supporter, benzoyl phenyl hydroxylamine and dithizone as ligands for Pb and Cr ions respectively, 4-vinyl pyridine as functional monomer, ethylene glycol dimethacrylate as crosslinker and 2, 2′-azobis(isobutyronitrile) as the initiator. The ionic templates were achieved using HCl 2M as an eluent solution. The chemical structure, morphology, thermal behavior and magnetic properties of the sorbent polymers were evaluated using Fourier-transform infrared spectroscopy, scanning electron microscopy, thermal gravimetric analysis and vibrating sample magnetometry methods. Optimization of affecting parameters of the adsorption of analytes (adsorption time, pH, kind and concentration of the eluent solution, elution time and temperature) were performed using flame atomic absorption spectroscopy method. The results showed that the maximum adsorption capacities for lead and chromium at 40 ◦ C were 92. 3 and 96. 8 milligrams per gram at pH of 6 and 3 respectively. The synthesized sorbents had high selectivity and were successfully applied for these pollutants removing from waste waters in vdifferent stages of ammonium perchlorate production process.

In this research, the effect of the amount of strain and rolling temperature on the microstructure and the hardness of the explosively bonded 304 stainless steel-copper sheets were investigated. Explosive welding was performed using two explosive thickness of 46 and 79 mm with a stand-off distance of 2 and 3 mm. The results of the optical microscope after welding showed that all samples had a common wavy interface. The results of scanning electron microscopy and EDS analysis showed that in all samples the melting region was observed in the joint. The results of micro-hardness tests showed that the most hardness in interface was the sample with the highest thickness of the explosive and the stand-off distance. Rolling operations were carried out with a thickness reduction of 2 mm in two different conditions without preheating and preheating at 300 ℃ and 30 minutes. The results of the optical microscopy after rolling showed that in all cases after rolling, a decrease in the amplitude of the waves (wavelength thickness) was created. The results of the scanning electron microscopy and EDS analysis in the post-rolling and pre-heat conditions indicated that as a result of pre-heat before rolling operation, the copper and iron elements diffused from the interface of copper melting-metal region. Investigating the results of post-rolling non-treating samples showed that hardness after rolling in all samples increased. But in pre-heated samples, the hardness was less than that of as-welded samples.

Polybutadiene acrylic acid acrylonitrile (PBAN) is binder for composite solid propellants used in spacecraft systems, curing kinetics of which is very important. In this research, the effect of functionality of epoxy curative on the curing kinetics of PBAN is researched. Equivalent stoichiometric ratios of PBAN and di-functional (DER 331) and tri-functional (LY 5052) epoxy curatives was cured at 80º C. During curing reaction, 16 in-situ FT-IR spectra were obtained from the samples to monitor the progress of ester group formation (curing progress). Curing reaction of PBAN with both curatives consists of two separated steps with dissimilar kinetics. Transition from first step to second step of curing reaction, for difunctional curative is occurred after 7 days while, for tri-functional curative after 3 days. The rate of curing reaction using di-functional epoxy curative, is approximately half of tri-functional epoxy curative. These results are important in the aspect of production process and mechanical properties of final product.

In this research, with evaluation of the solubility of cyclotetramethylene tetranitramine (HMX) explosive in different concentrations of water-methyl ethyl ketone (MEK) solvent, at a temperature range of 40-70 ° C, the solubility and some thermodynamic parameters such as enthalpy of dissolution and mixing were calculated. Thereafter, in order to increase the capacity of the crystallization process, the effect of digestion of HMX in evaporative crystallization procedure on the morphology and polymorph conversion of crude HMX was investigated using electron microscopy, X-ray diffraction (XRD) and Raman spectroscopy. Then, two quantitative methods based on the XRD and Raman spectroscopy were developed for the determination of -HMX in -type samples. The results showed that with the mentioned methods, -polymorph can be determined in the linear dynamic range of 0. 32-5. 25 wt. % in -HMX. Also, the crystallization studies in MEK using digestion and evaporative crystallization showed complete conversion of crude HMX polymorphs to -type, along with significant increasing in the crystallization capacity.

Hematite iron oxide (α-Fe2O3) is used in military industries as a main component of thermite mixtures, burning rate catalyst of composite propellants and pyrotechnic igniter systems. Catalytic and oxidation activity of this mineral combination increases strongly with reduction of particle size. In this research, nanoparticles of hematite iron oxide was synthesized by a new co-precipitation method by using iron (III) nitrate monohydrate in alkaline environment (pH=11). In order of completion of oxidation, hydrogen peroxide 35% was added in the final step. Product was analyzed by SEM, TEM, FT-IR and XRD techniques after separation and drying at 60 ° C. SEM and TEM images indicated that the product is rodshape by mean diameter of 40 nm and length of 150 nm. Afterward, this product was applied in incendiary thermite formulation. Results showed that the thermite formulation containing nano 𝐹 𝑒 2𝑂 3 has more intense ignition effects compared to the same composition containing micronized 𝐹 𝑒 2𝑂 3. Burning time of these formulations were 3 and 4 sec respectively. Furthermore, the hole diameter created in steel target increased about 23% by using nano-iron oxide.

A new high energetic copper(II) complex, [Cu(μ-DAMT)Cl2]2, was prepared by the reaction of 4, 5-diamino-3-methyl-4H-1, 2, 4-triazol-1-ium chloride (DAMT. HCl) with copper(II) nitrate and identified by elemental analysis, spectral characterization (FT-IR), melting point and molar conductivity. The spectral and physical characterizations of the product confirm the formation of a binuclear structure of copper(II). In the predicted structure of the complex, copper atom has a coordination number of four with a square planar geometry and CuN2Cl2 environment. In the copper complex, the DAMT ligand acts as N2-donor through its 2 and 3 triazolic sp2 nitrogen atoms. The amine nitrogen atoms do not participate in the coordination process. Thermal property of the ligand and complex was studied by TGA/DSC thermogram. These data reveals that although the salty ligand has an endothermic decomposition whilst after coordination to the copper atom, forms a high energetic complex with exothermic decomposition. This complex releases – 279. 08 Jg– 1 energy during the second step of decomposition in thermal range of 262-271 ° C.