RDX Content Research Articles

Research on fabrication technology of PVV-5AVN explosive for explosive reactive armor

PVV-5AVN explosive is a type of polymer-bonded explosive (PBX that typically comprises a mixture of RDX (hexogen), a high-explosive compound, and a polymer binder such as polyisobutylene. It finds extensive application in various generations of explosive reactive armor. This study investigates factors influencing the quality and specifications of PVV-5AVN explosives, including solvent choice, solvent ratio, mixing time, and ingredient proportions. Specifically, the RDX content is 85 ÷ 91%, and the binder system content is 9 ÷ 15% (with a DOS/PIB mass ratio of 2.75). These findings establish a fabricating process for laboratory-scale PVV-5AVN explosives that meets technical standards comparable to existing literature.

Characteristic Property of Combustion and Internal Ballistics of Triple-Based Propellant according to Particle Size of RDX

The important factors in the design of the gun propellant are impetus, flame temperature and pressure. In this paper, we considered a nitrocellulose based propellant composition that replaced sensitive NG(Nitroglycerin) with RDX(Cyclotrimethylenetrinitramine) and DEGDN(Diethylene glycol dinitrate) which high energy and low sensitivity. Particle size and content of RDX are the two main factors that affect the burning stability of RDX-based propellants. Among them, the characteristics of the propellant according to the particle size of RDX were confirmed. The relative combustion rate(R.Q., Relative Quickness) of the propellant changed according to the RDX particle size, and internal ballistics of properties of propellant were also varied. The particle size of RDX can be confirmed as a major factor in the combustion and internal ballistics characteristics of the propellant.

Investigation into the ignition sensitivity and detonation kinetics of Al/RDX energetic dust

Given the prevalence of Al/RDX energetic dust in industrial production, this study investigates their ignition safety and explosion hazards using Hartmann tubes and 20 L spherical explosion containers. The minimum ignition energy (MIE) increases from 20 mJ to 55 mJ as RDX content increases, indicating that adding RDX enlarges the effective particle size of the dust, thereby reducing its ignition sensitivity. A logistic regression model was used to develop a fitting equation for ignition probability, correlating dust concentration and ignition energy. The flame propagation velocity and explosion pressure of the energetic dust initially increase and then decrease with increasing RDX content. Optimal combustion characteristics were observed at 20 % RDX, with the maximum flame propagation velocity of 101 m s−1. However, the peak flame temperature decreases with increasing RDX content. The maximum explosion pressure and maximum explosion index at 1.77 MPa and 186.99 MPa m s−1 respectively, at 40 % RDX content. These findings highlight that 20 % RDX content yields the best combustion characteristics, while 40 % RDX content offers the maximum explosive potential, providing valuable insights for enhancing safety measures in industrial applications involving energetic dusts.

Investigation of Flame Structures of Double-Base Propellant and Modified Double-Base Propellant Containing Nitramine Using OH-PLIF and Kinetic Simulation.

The combustion behavior of various propellant samples, including double-base propellants, pressed nitramine powders, and modified double-base propellants containing nitramine, was examined using OH-PLIF technology. The combustion process took place within a combustion chamber, and images capturing the flame at the moment of stable combustion were selected for further analysis. The distribution and production rate of OH radicals in both the double-base propellant and the nitramine-modified double-base propellant were simulated using Chemkin-17.0 software. The outcomes from both the experimental and simulation studies revealed that the concentration of OH radicals increased with a higher content of NG in the double-base propellant. In the modified double-base propellant containing RDX, the OH radical concentration decreased as the RDX content increased, with these tendencies of change aligning closely with the simulation results.

Comparative study on detonation parameters of ammonium dinitramide and ammonium perchlorate in composite explosives

ABSTRACT Ammonium dinitramide (ADN) has the advantages of chlorine free, low characteristic signal and high energy compared with ammonium perchlorate (AP), which is the most likely oxidant to replace ammonium perchlorate. Therefore, we conducted theoretical calculations to analyze the influence of oxidant content and RDX content on the detonation parameters of composite explosives. We compared the detonation parameters of ADN-based composite explosives with AP-based composite explosives, then verify the theoretical calculation analysis results through actual testing. The main research conclusions of this paper are as follows: (i) The detonation parameters of ADN based composite explosive are higher than those of AP-based composite explosive, in which the detonation velocity is about 3.3%~17.2% higher, the detonation heat is about 0.65% ~41.8% higher, and the explosion volume is about 1.6% ~11.6% higher; (ii) the average detonation velocity of the ADN-based explosives tested in practice is 20.4% and 3% higher than that of AP-based explosives respectively, which is basically consistent with the theoretical calculation results. However, the work capacity is lower than that of AP-based composite explosive.

Research on catalytic performance of transition-metal-based MOFs towards thermal decomposition of RDX

It is beneficial for the efficient energy utilization of propellants to develop high - efficiency catalysts for thermal decomposition of energetic materials. Herein, catalytic characteristics of different transition-metal-based MOFs on thermal decomposition of cyclotrimethylenetriamine (RDX) were studied, such as [Zn2(atz)3(N3)]n, MIL-88B and ZIF-67. ZIF-67 was found to exhibit superior properties therein. On this basis, size effect of ZIF-67 when catalyzing the thermal decomposition of RDX was further investigated. It has been found that the catalytic performance can be boosted as the size of ZIF-67 is reduced. However, the performance will decline when the size is ulteriorly reduced into nanoscale. Besides, the doping of Ni, Cu or Zn into ZIF-67 has little effect on the promotion of the catalytic performance. Among all the catalysts, ZIF-67-S shows the best catalytic performance for the thermal decomposition of RDX, which is superior to most existing catalysts. Specifically, it can reduce the thermal decomposition peak temperature of RDX by 22.4 °C and enhance the apparent decomposition heat by 59.9%. As a consequence, it is expected to be used as a combustion catalyst in propellants such as 3D printing gun propellants with high RDX contents.

Study on GAP Adhesive-Based Polymer Films, Energetic Polymer Composites and Application

To lay the foundation for environmentally friendly energetic polymer composites, GAP (glycidyl azide polymer) adhesive-based polymer films with different curing parameter R (mol ratio of hydroxyl/isocyanate) and energetic polymer composites with different RDX contents were studied. GAP/TDI (toluene diisocyanate)/GLY(glycerol) was selected as the adhesive system. The tensile strength and elongation at the break of the polymer film with R = 2.2, was 14.34 MPa and 176.86%, respectively, as observed by an AGS-J electronic universal testing machine. A relatively complete cross-linking network and high hydrogen bonding interaction were observed by LF-NMR (low-field nuclear magnetic resonance, where the cross-linking density was 11.06 × 10-4 mol/cm3) and FT-IR (fourier transform infrared spectroscopy, where the carbonyl bonding ratio was 64.84%). Forty percent RDX(hexogen) was added into the adhesive system. The tensile strength was 4.65 MPa, and the elongation at the break was 78.49%; meanwhile, the heat of the explosive was 2.87 MJ/kg, and the residue carbon rate was only 2.47%. The tensile cross-sections of energetic polymer composites were observed by SEM (Scanning electron microscopy).

Fabrication and properties of sphere CL-20/RDX composites with different molar ratios

ABSTRACT Micronsized spherical CL-20/RDX composites with uniform size were prepared by an electrospray method. After preparation, the morphology, crystal structure, thermal decomposition property, explosion performance and mechanical sensitivity were characterized. Different structures existed in the CL-20/RDX composites with different molar ratios. The CR11e composites had the lowest apparent activation energy and the lowest critical temperature of thermal explosion. The explosion pressure and mechanical sensitivity of CL-20/RDX composites were lower than that of raw CL-20 and decreased with increasing RDX content.

Contamination characteristics of energetic compounds in soils of two different types of military demolition range in China

The pollution of energetic compounds (ECs) in military ranges has become the focus of worldwide attention. However, few studies on the contamination of ECs at Chinese military ranges have been reported to date. In this study, two different types of military demolition range in China, Dunhua (DH) and Taiyuan (TY), were investigated and the ECs in their soils were determined. 10 ECs were detected at both ranges. While all the contamination characteristics were distinct, 2,4,6-trinitrotoluene (TNT) was the most abundant contamination source in soils at DH range, with an average concentration of 1106 mg kg−1 and a maximum concentration of 34,083 mg kg−1. Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and two mono-amino degradation products of TNT were also found to have high concentrations, with potential ecological and human health risks. In contrast, the concentrations of ECs in soils of TY range were much lower. The content of RDX was most significant, with average and maximum concentrations of 7.8 and 158 mg kg−1, respectively. However, the potential threat to human health of 2,4-dinitrotoluene and 2,6-dinitrotoluene in soils at both ranges should not be ignored. The differences in pollution characteristics of the ECs at DH and TY are closely related to the types and amounts of the munitions destroyed. Moreover, the spatial distribution of ECs at the demolition ranges was extremely heterogeneous, which may be attributed to the use of open burning / open detonation and the non-homogeneous composition of the munitions.

Deflagration to detonation transition in weakly confined conditions for a type of potentially novel green primary explosive: Al/Fe2O3/RDX hybrid nanocomposites

The properties of the combustion and deflagration to detonation transition (DDT) of Al/Fe2O3/RDX hybrid nanocomposites, a type of potentially novel lead-free primary explosives, were tested in weakly confined conditions, and the interaction of Al/Fe2O3 nanothermite and RDX in the DDT process was studied in detail. Results show that the amount of the Al/Fe2O3 nanothermite has a great effect on the DDT properties of Al/Fe2O3/RDX nanocomposites. The addition of Al/Fe2O3 nanothermite to RDX apparently improves the firing properties of RDX. A small amount of Al/Fe2O3 nanothermite greatly increases the initial combustion velocity of Al/Fe2O3/RDX nanocomposites, accelerating their DDT process. When the contents of Al/Fe2O3 nanothermite are less than 20 wt%, the DDT mechanisms of Al/Fe2O3/RDX nanocomposites follow the distinct abrupt mode, and are consistent with that of RDX, though their DDT processes are different. The RDX added into the Al/Fe2O3 nanothermite increases the latter's peak combustion velocity and makes it generate the DDT when the RDX content is at least 10 wt%. RDX plays a key role in the shock compressive combustion, the formation and the properties of the DDT in the flame propagation of nanocomposites. Compared with RDX, the fast DDT of Al/Fe2O3/RDX nanocomposites could be obtained by adjusting the chemical constituents of nanocomposites.

Effects of particle size and content of RDX on burning stability of RDX-based propellants

Particle size and content of RDX are the two main factors that affect the burning stability of RDX-based propellants. However, these effects and the corresponding mechanisms are still controversial. In this work, we investigated the physicochemical processes during burning and the corresponding mechanisms through the technologies of structure compactness analysis on the base of voidage measurement and theoretical interfacial area estimation, apparent burning rate measurement using closed vessel (CV) and extinguished burning surface characterization relying on interrupted closed vessel (ICV) and scanning electron microscope (SEM). The results indicate that the voidage increased with the increase of RDX content and particle size due to the increasing interfacial area and increasing interface gap size, respectively. The apparent burning rate increased with the increase of RDX particle size because of the decreasing RDX specific surface area on the burning surface, which could decrease the heat absorbing rates of the melting and evaporation processes of RDX in the condensed phase. Similarly, the apparent burning rate decreased with the increase of RDX content at pressures lower than around 55 MPa due to the increasing RDX specific surface area. Whereas, an opposite trend could be observed at pressures higher than around 55 MPa, which was attributed to the increasing heat feedback from the gas phase as the result of the increasing propellant energy. For propellants containing very coarse RDX particles, such as 97.8 and 199.4 μm average size, the apparent burning rate increased stably with a flat extinguished surface at pressures lower than around 30 MPa, while increased sharply above around 30 MPa with the extinguished surface becoming more and more rugged as the pressure increased. In addition, the turning degree of u-p curve increased with the increase of coarse RDX content and particle size, and could be reduced by improving the structure compactness.

Preparation and characterization of RDX based composite energetic materials with a cellulose matrix

AbstractCyclotrimethylenetrinitramine (RDX)‐based high‐energy explosives are widely used in weapon warheads, propellants, and ammunition. Many studies have explored different supporting structures for RDX; however, the use of natural materials have rarely has been reported. Natural cellulose is widely known for its excellent compatibility and loading capacity. In this study, cellulose was used as a supporting structure and insensitive material for RDX composites. Cellulose/RDX composite aerogels (RCAs) were prepared using 1‐allyl‐3‐methyl imidazole (AMIMCl) as the solvent, and their properties were characterized. The results show that the content of nitrogen in cellulose/RCAs was 34.5%, and the content of RDX was as high as 94.3%. Moreover, RDX particles were attached to the fibers inside the cellulose aerogels (CAs), forming a homogeneous protective layer on the surface of the cellulose matrix. Compared with the raw RDX material, the thermal stability of the cellulose/RDX energetic aerogels was greatly increased. The porosity of the CAs was reduced due to RDX particles growing inside the CAs. The impact sensitivity increased from 35 to 78 cm.

Development rheological and thermal properties of a novel propellant RDX/TEGDN/NBC

To meet the high energy and high strength requirements of advanced propellants, a novel propellant RDX/TEGDN/NBC was designed by hexogen that was also called RDX and triethylene glycol dinitrate/nitrated bacterial cellulose (TEGDN/NBC) composite. The basic properties such as structure, morphology and thermal properties were characterized by fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and simultaneous thermal analysis (TG-DSC). The rheological properties were measured by rheometer and the effects of RDX content were studied by steady flow and dynamic test in detail. The results showed the added RDX of RDX/TEGDN/NBC composites solutions could destroy the stable structure of the system. Under the external force, RDX/TEGDN/NBC composite solution exhibit a better fluidity compared with TEGDN/NBC composite solution. And with the RDX increase, the viscosities of the solution systems decreased first and then increased, reached their minmum values when the RDX content was 15 wt%.

Energetic metastable Al/CuO/PVDF/RDX microspheres with enhanced combustion performance

Nanothermites have a promising study in micro propellant due to its faster reaction rate, higher energy-release efficiency, and significantly enhanced combustion performance. However, most thermites prepared by physical mixing are easy to separate during the propellant preparation process, significantly impeding the embodiment of the advantages of thermite. In this study, Al/CuO/PVDF microspheres incorporating high explosive RDX have been successfully assembled by electrospray technology. The thermal and combustion performance of the composite microspheres have significantly improved. They have shorter delay time, burning time, and higher pressure, pressurization rate than the physical mixtures, which are attributed to their uniform structure and the interaction of the components. And based on combustion tests, the combustion performance of microspheres is mainly affected by the content of RDX. These results indicate that the electrospray technology and adding RDX into microspheres are effective methods to prepare nanothermites with enhanced reactivity.

Energy characteristics and mechanical properties of cyclotrimethylenetrinitramine (RDX)-based insensitive high-energy propellant

In order to improve the energy performance and mechanical properties of insensitive high-energy propellants, cyclotrimethylenetrinitramine (RDX)-based insensitive high-energy propellant with nitrocellulose (NC) and glycidyl azide polymer-energetic thermoplastic elastomer (GAP-ETPE) blends as the binder was prepared by solvent method. The effects of GAP-ETPE/NC ratio and RDX content on the energy properties of propellants were analyzed by numerical calculations. The effects of GAP-ETPE/NC ratio, RDX particle size and RDX content on the mechanical properties of propellants were studied by compression test, impact test and solid surface properties test. The impact sensitivity and friction sensitivity of all the propellant compositions were tested. The theoretical calculation results showed that the introduction of GAP-ETPE into propellant significantly decreased the explosion temperature and increased the specific volume. The density, compression strength, and surface energy of the propellant were gradually decreased with increasing the GAP-ETPE/NC ratio, and the impact strength was increased gradually as well. The mechanical properties and surface energy of the propellant were improved greatly when the RDX particles were smaller. The studied propellants showed a linear increase in the propellant force and explosion temperature with increasing the RDX content. However, increasing the RDX content significantly reduced the impact strength and surface energy. Mechanical reinforcement with solid fillers increased the compression strength and propellant density to a certain degree. Compared with the standard propellants SF-3, the prepared propellant composition is insensitive to the impact and friction.

Development of the Detonation Nanodiamond Synthesis from Tetryl Based Ternary Mixtures

The process of detonation synthesis of nanodiamonds from ternary systems was developed with conversion tetryl as their main component. The dependence of the yield of detonation nanodiamonds and their content in the diamond blend on the tetryl content in the ternary composition was shown as well as that of the yield of detonation nanodiamonds on the oxygen balance of the blend. The conditions and composition of the explosive were found to determine the maximum yield of detonation nanodiamonds, 8.2 wt %, based on which it is possible to develop a more economical and efficient industrial technology for the production of detonation nanodiamonds: the use of explosive compositions containing 50 wt % or more conversion tetryl, respectively, a decrease in the content of expensive and scarce RDX; high content of nanodiamond in the diamond blend, which reduces the cost of chemical cleaning; the possibility of a simple selection of the required oxygen balance of the explosive composition.

High-substitute nitrochitosan used as energetic materials: Preparation and detonation properties

In order to develop new high-energy materials utilizing natural products, a high-substitute nitrochitosan was prepared with different methods. Prepared processes and detonation properties of the nitrochitosan samples were systematically studied. The nitration substitute degree, nitrogen content, exothermic decomposition enthalpy, heat of combustion, impact sensitivity, detonation velocity and detonation pressure of the prepared high-substitute nitrochitosan were 2.01, 16.67 %, −2226 J g−1, −7831.6 ± 116.3 J g−1, >14.2 J, 7.81 km s−1, and 24.03 GPa, respectively. Compared with nitrocellulose (NC), the nitrogen content, impact sensitivity and detonation properties of the prepared nitrochitosan were significantly improved. Nitrochitosan and RDX can form a uniform composite in acetone. With the increase of RDX content, the impact sensitivity of composite increased, but the composite was more stable and not easy to decompose. High-substitute nitrochitosan presents a potential application in solid propellants.

Ignition and Combustion Characteristics of Al/RDX/NC Nanostructured Microparticles

ABSTRACT Nanostructured microparticles composed of nanoaluminum, 1,3,5-trinitrohexahydro-s-triazine (RDX), and nitrocellulose (NC) were produced using electrospray assembly and studied in an experimental investigation of their ignition and combustion characteristics. All particles contained 5% NC by weight, while the nanoaluminum content ranged from 23.75 to 85.5% by weight, with the balance being RDX. T-jump wire ignition and laser ignition experiments were conducted with pressures ranging from 0.101 to 5.17 MPa. The T-jump experiments demonstrated that the aluminum component of the particle at least partially combusted anaerobically with the combustion products of the RDX and NC. This was further verified by laser ignition experiments in an inert environment via emission spectroscopy. Broad band light emission was used during laser ignition experiments to characterize ignition delay in both air and inert environments (nitrogen or argon). Ignition delay was independent of gaseous environment suggesting that particle ignition was driven by the decomposition/combustion process of RDX and NC. Ignition delay decreased with decreasing RDX content at 0.101 MPa and decreased asymptotically with increasing pressure.

Effect of RDX content on the agglomeration, combustion and condensed combustion products of an aluminized HTPB propellant

Cyclotrimethylene trinitramine (RDX) is widely used in aluminized solid propellants to increase specific impulse. Experimental investigations on the effect of RDX content on the propellant combustion and agglomeration were thoroughly conducted based on Thermogravimetry-differential scanning calorimetry, laser ignition, combustion diagnosis and a new home-made condensed combustion products (CCPs) collection device. The results show RDX inclusion inhibits the decomposition of AP. The ignition delay and self-sustaining combustion time of aluminized propellant increase, while the combustion intensity decreases with increasing RDX content. RDX addition is found to decrease the burning rate within 6–10 MPa. Compared with the baseline propellant, RDX leads to obvious aggravation of aluminum agglomeration on the propellant burning surface. The 6 wt% and 12 wt% RDX-included propellants increase the average CCPs size from 46.3 μm to 86.7 μm and 96.6 μm, respectively. The combustion efficiency of aluminum in propellant is reduced by 15% when the RDX content is increased from 0 to 12%. Overall, RDX plays a comprehensive effect on the ignition, combustion and agglomeration characteristics of aluminized propellant. Results of this study can help guide the application and development of RDX in aluminized propellants for solid rocket motors.

High Volumetric Specific Impulse Composite Propellant Based on Terminally Functionalized Block Copolymers of Polybutadiene and ϵ‐Caprolactone

AbstractFor enhanced range, higher payload capacities and for miniaturized propulsion systems, today's strategic and tactical weapon system designers demand for higher density and specific impulse of the propellant. In order to enhance the density impulse of HTPB/DOA/RDX/AP/Al based composite propellant, studies have been carried to replace conventional HTPB/DOA binder system with hydroxyl terminated block copolymer of polybutadiene and ϵ‐caprolactone with NG as plasticizer. Total eight numbers of compositions were formulated with varying content of RDX. Both binder systems were compared in propellant compositions by evaluating various physical, thermal and ballistic properties. Various rocket performance parameters of each formulation were theoretically predicted by NASA CEC‐71 program and burning rate was measured in pressure ranges of 3‐7 and 7‐11 MPa by the acoustic emission technique. In addition, density, viscosity build up, calorimetric values, thermal decomposition and sensitivity parameters of each composition were also assessed and compared. In an outcome, it was concluded that HTBCP25/NG based propellant compositions enhance the density by 4.4–5 % and calorimetric values by 12–15 % as compared to HTPB/DOA based compositions. Strand burning rate data show enhancement of burning rate by 40–70 % at 7 MPa pressure in HTBCP25/NG based compositions. Impact and friction sensitivity data also revealed their utility in propellant compositions for future applications.