محمدعلی ذرعی

In this research, 4,2-dinitroanisole was synthesized through nitration of chlorobenzene by sulfuric acid and nitric acid, and then methylation of 4,2-dinitrochlorobenzene was done by sodium hydroxide and methanol. The effective parameters in the reaction, including temperature, time, molar ratio of reactants, catalyst, etc., were optimized by Minitab 18 software and Taguchi method. In the first step, 4,2-dinitrochlorobenzene was synthesized through the nitration of chlorobenzene by reducing the reaction time and increasing the yield, and then DNAN was synthesized through the methylation of 4,2-dinitrochlorobenzene by reducing the reaction time and temperature in the absence of a catalyst and increasing the synthesis yield. Also, HOMO and LUMO energy levels in DNAN were calculated with B3LYP/6-311G ++ (d,p) basis level -8.2203 and -4.3386 eV, respectively.

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.

Today, vacuum stability test is one of the best methods to investigation the compatibility of different plasticizers and polymers. In this research, the compatibility of polydimethylsiloxane resin with trimethylolethane trinitrate energetic plasticizer was investigated. The applied approaches included vacuum stability test (VST) and glass transition temperature determination using DSC analysis. The acceptance limit of TMETN plasticizer by polydimethylsiloxane resin was determined using retardation and it was found that this polymer can accept the plasticizer at least 20% (w/w). Investigating the glass transition temperature with DSC analysis test showed that polydimethylsiloxane has good compatibility with TMETN plasticizer. The amount of gas released from the sample in standard conditions (VR) in the VST test was calculated as 4.77 cm3, which was within the allowed range and indicates the compatibility of TMETN plasticizer with polydimethylsiloxane.

The storage time of propellants is one of the important issues, the determination of which requires a precise analysis of the kinetic parameters of the decomposition reaction. One of the methods of investigating the decomposition reaction and determining the kinetic parameters of the thermal decomposition reaction is the use of thermal analysis. in this thesis, the thermal degradation reaction in a composite solid propellant sample based on PDEGA was investigated at several heating rates 5,10,15○C/min using differential scanning calorimetry (DSC). Then, using the model-free method of Kissinger and Ozawa, the average activation energy was determined at about 136 kJ/mol, then using a vacuum thermal stability test (VST), parameters of pressure and time in 3% degradation were obtained as 0.07563 bar and 91 hours, respectively and finally The shelf life of 38 years was calculated with Arrhenius mathematical equation.

1,4-dinitrocyclohexane-2,3,5,6-tetranitrate is one of the strongest cyclic nitrate ester plasticizers, which is used as a new generation of plasticizers in the formulation of energetic materials. In this research, the mentioned compound was synthesized and optimized in two steps through experiment design using the Minitab 18 software (Surface Response Method) on temperature, time, and the molar ratio of reactants parameters. In the first step, 1,4-dinitrocyclohexane 2,3,5,6-tetraol was synthesized and optimized by an easy method using glyoxal and nitromethane reactants in an alkaline environment at a temperature of 10 °C for two hours, and confirmed by FT-IR and 1H-NMR spectra. In the second step, 1,4-dinitrocyclohexane-2,3,5,6-tetranitrate was synthesized with a decomposition temperature of 191 °C, and a yield of 73.56% by nitration of the 1,4-dinitrocyclohexane-2,3,5,6-tetraol with nitric acid and acetic anhydride at a temperature of 20 °C for four hours. This compound was analyzed and characterized with the help of FT-IR, 1H-NMR, and DSC-TGA.

Today, the need for high-energetic materials with high thermal stability is felt in various military and civilian industries. Melamine-based compounds have attracted the attention of researchers in this field since many years ago, with various characteristics, including a nitrogen-rich structure with intra- and intermolecular hydrogen bonds.The use of melamine structure and its salts in the formulation of solid composite propellants in different roles improves their functional properties. In addition, recently, the synthesis of several high-energetic salt based on the melamine dioxide molecule was an effective step towards the development of a new generation of high-energetic materials; These new salts are in the form of structures with intramolecular fuel and oxidizer; and the investigations show that three monoanionic salts (MDOP, MDOMN and MDONA) with having detonation velocities in the range of 8711-9085 (m.s -1 ) are comparable to the conventional compound RDX, while the sensitivies to impact (IS: 23-27 J) and friction (FS: >240 J) in these salts are much lower than RDX, HMX and AP.

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.

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.

Being non-polar and considerably high electrical resistivity are significant drawbacks of the crystalline paraffin wax used for desensitizing energetic materials. Herein, as a practical approach to improve the wax properties, maleic-anhydride was reacted with paraffin wax in the presence of a free-radical initiator. Then, the reaction success was approved by employing Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) to spot carboxyl groups onto the aliphatic backbone. In addition, the thermal properties of the modified wax were investigated using differential-scanning-calorimetry and thermogravimetry analysis (DSC-TGA). Finally, to estimate the improvement in the wax polarity, an experiment was designed in which HMX coated via a two-step procedure was conducted for DSC and tribocharing tests. The second layer utilized 0.5 w% glyceline as a deep eutectic solvent (DES). In brief, our observation exhibited that the modified wax caused a 50% decrease in charge accumulation compared to the unmodified paraffin. In addition, our experimental outcomes .showed that the modified paraffin exhibited a better distribution over the substrate surface than the unmodified one.

CL-20 is the most energetic conventional explosive available for military use. The overall aim of the high energy material research community is to increase yield and reduce cost of CL-20. All synthetic routes used to prepare the CL-20 depended on the condensation reaction of benzylamine with glyoxal for preparation of HBIW intermediate. In the presence of HCOOH as catalyst, yield of 75% is reported. In this paper we investigated the effect of lewis acid catalyst on the yield of HBIW. The results suggested that the more efficient catalyst (such as MgSO4, ZnCl2, CuSO4, Mg(ClO4)2 increase yield, 25% more than previously reported.