Papers by Keyword: RDX

Abstract: Intermolecular interaction of mononitrotoluenes (MNs) plasticizer with 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitrohexahydro-1,3,5-triazine (RDX) was experimentally and theoretically investigated. The basis set superposition error (BSSE) and interaction energy of TNT, RDX and plasticizers were computed at MP2/6-311++G** levels. Compared with the weak E_inter between RDX and TNT (−1.586 kJ/mol), E_inter between the o-nitrotoluene and TNT and RDX can increase to −131.557 kJ/mol and −48.487 kJ/mol, indicating there is strong intermolecular-interaction. SEM imagines also show that mononitrotoluene could form layered deposits in TNT and closely surround RDX crystalline. MD simulation results indicate that tensile modulus of (100) TNT and (100) RDX increases when introducing mononitrotoluene plasticizers separately, which agree with the experimental phenomenon of Brazilian disk test.

Abstract: Solid composite propellants are extensively used for propulsion of rockets, missiles and space applications. The composite propellant is a polymeric matrix in which the oxidizer and fuel particles are embedded in a polymeric binder. Different composite propellant mixtures have been prepared using ammonium-perchlorate (ratio 70:30) as oxidant and mixture of aluminium powder (ratio 50:50) as metal component. In the present work, RDX (Cyclotrimethylene trinitramine) has been used in successive increments replacing AP (Ammonium Perchlorate) in number of batches by varying the percentage of solid loading, and studied their different properties such as viscosity build-up, mechanical and ballistic properties.

Abstract: The solubility of TNT and RDX was measured in supercritical carbon dioxide fluid at 303.0, 308.0, 323.0, 338.0 K, and over the pressure range from 10.0 MPa to 50.0 MPa. This study examined the influences of extraction temperature, extraction pressure and support effect (SE) between molecules of TNT and RDX on their solubility in the TNT/RDX/SC-CO₂ system. The results show that solubility of TNT and RDX in TNT/RDX/SC-CO₂ ternary system is much higher than that in binary system. The values of SE of RDX and TNT increase first and decrease then with the pressure changing. The pressure turning point occurred over the pressure range from 25 MPa to 28 MPa for TNT and from 13 MPa to 20 MPa for RDX.

Abstract: The Al₂O₃ is synthesized by detonation of mixed explosive, prepared by mixing RDX and aluminum hydroxide named as precursor of thermal decomposition. The production of detonation is analysed by XRD, TEM and DTA/TG. The curve of XRD indicates that the production are (α+γ)-Al₂O₃. The average crystal size of Al₂O₃ is 126nm calculated by the Scherrer equation. The photographs of TEM show that all granules of Al₂O₃ are spherical, and the average size of granule is 1000nm. The visible exothermic or endothermic peak does not appear on the curve of DTA from 50 to 1300 degree Centigrade. The curve of TG indicates that the production of detonation generates 12% weight loss from 50 to 1300 degree Centigrade.

Abstract: The drying characteristics of Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) are investigated in the ranges of 60-90°C of drying temperature under two vacuum conditions in a laboratory scale dryer. The effect of drying temperature and absolute pressure on the drying characteristics is determined. In order to estimate and select the suitable form of RDX drying curves, the curves are fitted to ten different semi-theoretical and/or empirical thin-layer drying models and coefficients are evaluated by non-linear regression analysis. The models are compared based on their coefficient of determination, such as mean bias error, root mean square error, reduced chi-square and modeling efficiency between experimental and predicted moisture ratios. It is deduced that Midilli-Kucuk model has shown a better fit to the experimental drying data as compared to other models. A diffusion model is used to describe the moisture transfer and the effective diffusivity for RDX drying is also determined at each temperature. Beside, the activation energy is also expressed using Arrhenius-type relationship under atmospheric pressure and vacuum conditions.

Abstract: The cyclotrimethylene trinitramine(RDX) added into gun-propellants can improve the energy of the gun-propellants, but influence their mechanical properties. Under the suitable experimental conditions by using the compression test and drop hammer test, the influence to mechanical properties of gun-propellants by RDX content is obtained. The results indicate that with the increase of RDX, the compressive strength of gun-propellants increases, but impact strength decreases. While, the compressive strength of gun-propellants decreases, but impact strength increase when the temperature rises.

Abstract: In the present study, Zn-hydroxyapatite (Zn-HA) was synthesized, the powder was thermally treated at different temperatures and then characterized. The Zn-HA powder was characterized mainly by FTIR and XRD, but have been performed investigations like SEM, BET and size distribution. The addition of ZnO in hydroxyapatite causes alleged interactions with the existing groups in HA, which amend the corresponding signals to these groups in the IR spectra. X-ray diffractograms for samples (untreated and heat-treated) have been recorded and microstructural parameters for the all samples have been calculated. The obtained average sizes of the crystallites and the network tensions support the idea that Zn-HA powders are nanostructured. The SEM images and size distributions for Zn-HA indicate a cluster of crystals with nanometer-scale of the population-base. Was determined the adsorption-desorption isotherms for Zn-HA powder at 100 o C and 800 o C. The dates obtained from the analysis of particle size distribution indicates for the Zn-HA powder an size distribution for granules in the range from 0.05 to 0.3μm

Abstract: The thermal decomposition kinetics of RDX at different rates was studied by thermogravimetric analyzer(TG) and the activation energy of RDX was calculated by distributed activation energy model. It is shown that the thermal decomposition processes of RDX were divided into three stages according to the TG curves, they are molten stage, thermal decomposition stage and eng stage. The activation energies of RDX are all between 124.34 and 181.48KJ•mol-1 in the thermal decomposition stage of non-monotonously increasing. The activation energy of RDX is 139.98 KJ•mol-1 in the molten stage, and the thermal decomposition stage is167.24KJ•mol-1.

Abstract: The constructed Sb-doped SnO2 electrode was obtained for electrochemical degradation of RDX. The influences of current density and initial concentration of RDX on electrochemical degradation of RDX were studied. Kinetics analysis shows that the electrochemical degradation of RDX follows the pseudo first-order reaction. The mechanism of electrochemical degradation of RDX was also discussed.

Abstract: The main factors affecting the drying process of RDX and the optimum drying conditions were investigated through single factor test and response surface methodology, the optimal drying conditions were gained. The results show that moisture content, vacuum, temperature are important factors in the drying process of RDX, the significance of main influencing factors is: temperature> vacuum> moisture content, the suggested drying condition is: 80°C for temperature, 0.05MPa for vacuum, 10% for moisture content.