Low-temperature Decomposition Research Articles

Phase equilibria in the Al–Fe–Mo system

This paper presents the results of our comprehensive study of phase equilibria in the Al–Fe–Mo system using DTA, X-ray diffraction, SEM and electron probe microanalysis. The liquidus and solidus projections were constructed. It is shown that the ternary compound Al8FeMo3 (τ) melts congruently at >1500 °C and has a homogeneity range from 2 to 9 at.% Fe and from 23.5 to 25 at.% Mo. Isostructural phases (Mo), (αFe) and AlMo (W-type structure, cI2-Im-3m) at solidus temperatures form a continuous solid solution (αFe,Mo,AlMo). Unlike the AlMo binary phase, which is not retained by quenching, the ternary (αFe,Mo,AlMo) phase is easily quenched due to its lower decomposition temperature. Among the binary based phases, the Al8Fe5 (ε) phase has the widest homogeneity region, which extends up to 24 at.% Mo at solidus temperatures. It is shown that the addition of Mo stabilizes the Al8Fe5 (ε) phase, and the temperature of its formation in the ternary system increases to 1331 °C in contrast to 1234 °C in the binary. Moreover, according to XRD data, the Al8Fe5 (ε) phase in the ternary system has a rhombohedral structure of the Al8Cr5-type (hR78-R-3m), rather than cubic Cu5Zn8-type structure (cI52-I-43m), like the binary one. A new binary compound Al45Mo7 was identified for the first time. Its crystal structure is established as monoclinic Al45V7-type (mS104-C2/m) with the lattice parameters a = 20.534, b = 7.561, c = 10.910 Å, β = 107.33. It was shown to form by peritectic reaction L + Al5Mo ⇄ Al45Mo7 at ∼800 °C. Iron additions stabilize the Al4Mo phase, which in the binary system is stable above 942 °C.

Bioinspired Fabrication of an Insensitive Ammonium Perchlorate Core-Shell Composite with Polydopamine Coating.

In this research, an ammonium perchlorate/polydopamine (AP/PDA) core-shell composite was prepared in a non-aqueous solution to reduce the mechanical sensitivity of ammonium perchlorate (AP). The result showed that the AP/PDA core-shell composite could be successfully constructed in ethyl acetate solution with an AP recovery rate that reached 86%. The mechanical sensitivity of the obtained AP/PDA core-shell composite was significantly reduced with a PDA content of only 0.76%. The DSC and TG also indicated that the coating of PDA showed catalytic activity in the thermal decomposition of AP with a lower decomposition temperature and a decreased Ea value of AP. Thus, this study proposed a simple strategy for achieving a good balanced between harnessing the energy and ensuring the safety of ammonium perchlorate by significantly reducing its mechanical sensitivity by using a very low polydopamine coating layer content, and this shows great potential for the design and fabrication of insensitive energetic composites for use in propellants.

Compact SiOC ceramic composite nanofiltration membranes by slow dip coating for water purification

In this work, novel silicon oxycarbide (SiOC) ceramic composite nanofiltration membranes with high performance were successfully synthesized at low sintering temperatures by gradual dip-coating approach for the first time. The slow dip-coating process facilitated improved wetting and even spreading of the precursor solution across the substrate. This controlled method ensured the formation of uniform and continuous SiOC ceramic membranes without the introduction of substantial defects or irregularities. Consequently, the systematic approach minimized the occurrence of pinholes, cracks and other structural imperfections in the SiOC ceramic membranes. The synthesis of the SiOC separation layer involved the sintering of polymeric polysilicon as precursor, which caused a lower decomposition temperature in contrast to the conventional method employing silicon carbide powder for sintering. The specific feature enabled a sharp decrease in the sintering temperature which was required for the formation of the separation layer. The prepared SiOC ceramic composite nanofiltration membranes exhibited good permeability with high rejection of dye molecules (>95%) and maintained stable water flux for at least 24 h, showing good long-term stability during cross-flow filtration. This progress provides new approach for the fabrication of compact ceramic nanofiltration membranes with low sintering temperatures, high separation efficiency and enhanced stability.

Impacts of metal oxide crystalline structure on the decomposition of solid propellants under combustion heating rates

Ammonium perchlorate (AP) has been the oxidizer of choice for composite solid propellants for decades and has been the object of decomposition studies for safety monitoring. Typically, studies perform differential scanning calorimetry (DSC) or thermogravimetric analysis (TGA) to show how metal oxides (MO) commonly incorporated into propellants alter AP decomposition rates and completeness of reaction. Most past decomposition work studies temperatures below the crystal phase transition (240°C) from orthorhombic phase to cubic, which impose internal stresses within the lattice of AP particles. Phase change induces a partial decomposition, which does not follow a shrinking core behavior; instead, it develops a network of pores up to a few microns in size throughout. During low-temperature decomposition, particles lose approximately 30-40 % of their mass. Simultaneous DSC/TGA (STA) use low heating rates for combustion environments but offer information on MO's catalytic and electron transport modifications. This work demonstrates how the crystalline morphology MO additives mechanistically alter the combustion properties of composite propellants by identifying modes for promoting decomposition in AP and HTPB. MO morphology determines the electron structure of the molecule, which sets the band gap properties of the particles. This study evaluated different morphologies and a range of MOs to identify the most active MO for decomposing A.P. Kissinger analysis was applied using STA data at heating rates of 10-, 20-, and 30-°C/min revealing significant shift in the high-temperature decomposition with a range of metal oxides. Higher heating rates were evaluated using CO2 laser ignition to identify the time to first gas using the MO that offers the best heat absorption, such as the aluminum oxides. This higher heating rate was found do more accurately represent the changes in the combustion rates in the final propellant mixture. Additionally, it was shown that electron transport additives like CuO show the most significant impact on combustion, and thermal absorbers offer the lowest impact on AP/HTPB combustion. This understanding offers a new approach to propellant design not previously presented and suggests future testing for tailoring the use of metal oxides in propellants.

Review on high-value utilization of phosphogypsum: Utilization of calcium and oxygen resources present in phosphogypusm

The world's annual production of phosphogypsum (PG) is up to 200 million tons at present. It was found that 15 % of PG produced worldwide is recycled. Therefore, it is imperative to seek a new pathway to recycle PG. This work provides an overview of the state-of-the-art scheme for high-value utilization of PG. Compared with previously published works, this review focuses on the utilization of oxygen (O) and calcium (Ca) resources. The state-of-the-art technology of utilizing O in PG consists of lignite’s chemical looping gasification (CLG) with PG-based oxygen carrier. The state-of-the-art technology for utilizing Ca in PG is the low-temperature decomposition of PG for producing CaO and CaCO3 from the reductive decomposition of PG. The process and the reaction mechanism of state-of-the-art technology for application of O and Ca in PG are summarized. Based on current research status, it is suggested to apply two or more solid wastes in cement, bricks and other aspects of large-scale. When utilizing PG, the migration transformation of impurities in PG and their reaction mechanisms at the molecular level deserve to be focused on. The key to solving the problems caused by PG large consumption, high value-added utilization and the introduction of policies providing incentives to this end. This research provides guidance for new engineering techniques for PG to achieve high-value and efficient use of resources in the large-scale utilisation of PG.

The effect of organophosphorus flame retardants on the combustion behavior and performance of poly (methyl methacrylate)

Maintaining transparency poses a challenge in the preparation of flame-retardant poly (methyl methacrylate) (PMMA). The feasibility of preparing flame-retardant transparent PMMA by incorporating oligomeric resorcinol bis(diphenylphosphate) (liquid), 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and hexaphenoxycyclotriphosphazene (solid) as additives has been explored. The impact of the flame retardants on the processing performance, thermal stability, combustion behavior and mechanical properties of PMMA has been investigated. The presence of organophosphorus compounds does not impact the transparency of PMMA and has a significant plasticizing effect. The modified PMMA displays a UL94 V-2 rating largely due to the formation of noncombustible droplets. However, the blend exhibits lower heat resistance, modulus and strength than does unmodified PMMA. The presence of organophosphorus compounds induces a higher limiting oxygen index (LOI) and reduced heat release for combustion of the blends than observed for PMMA without relying on charring, among which DOPO has a higher flame retardant efficiency due to its higher phosphorus content and lower decomposition temperature.

Facile recovery of lithium as Li2CO3 or Li2O from α-hydroxy-carboxylic acid chelates through pyrolysis and the decomposition mechanism

Chelation of lithium with readily available α-hydroxy carboxylic acids is a sustainable recovery method from spent Li-ion battery wastes as well as a possible lithium extraction method. In this work pyrolytic decomposition of a series of selected lithium chelates of glycolic, lactic, malic and tartaric acid were studied and compared with lithium acetate as a potential lithium recovery method from chelates. In thermogravimetric analysis, the four α-hydroxy carboxylic acid chelates studied showed lower initial decomposition temperatures in the 313–356 °C range, in comparison to the lithium acetate with an initial decomposition temperature of 444 °C. The ease of decomposition of α-hydroxy carboxylic acid chelates may be due to their favorable decomposition pathways through dimerization and tetramerization of α-hydroxy acids via esterification and free radical coupling mechanisms leading to a complex mixtures of products; including alkenes, dienes and enones. The lithium α-hydroxy carboxylic acid chelate pyrolysis residue formed above 300 °C was identified as lithium carbonate and further heating above 700 °C, lithium carbonate decomposes to lithium oxide, allowing the recovery of lithium as Li2CO3 or Li2O.

Unravelling the reaction mechanism for the AP decomposition over MgO: A density functional theory study and microkinetic simulation

The detailed reaction mechanisms for the decomposition of ammonium perchlorate (AP), an essential component of solid composite propellants, are poorly understood due to the ultrafast and complex reactions. Density functional theory and kinetic simulation are utilized to calculate the decomposition reaction of AP on the surface of magnesium oxide and present a detailed decomposition network. Using a proton transfer mechanism, NH3 and HClO4 are the major production at low-temperature decomposition of AP, involving two elementary steps. AP is completely decomposed in the high-temperature reaction stage. In this work, it is found that the decomposition of NH3 is mainly in the form of oxidative dehydrogenation, while HClO4 proceeds along the pathway HClO4→ClO3→ClO2→ClO→Cl, and the final nitrogen oxides, chlorine oxides are formed. These simulations provide offer atomic-level understanding of the complex reaction kinetics of AP, which can be applied to explore the reaction mechanisms of other metal oxides.

A functionalised interface for controllable decomposition of ammonium perchlorate by a self-assembly method

A functionalised interface construction strategy was developed by coating an ammonium perchlorate (AP) surface with quaternary ammonium cation surfactants using a self-assembly method. The functionalised interface transforms AP decomposition from high temperature decomposition into low temperature decomposition, and provides pressure-sensitive control over the mass ratio of AP decomposition in the two stages. Further study using molecular dynamics simulations and density functional theory reveal that the functionalised interface hinders the adsorption of NH3 molecules and promote the adsorption and decomposition of ClO4 on the AP surface, all of which could contribute to controlling AP decomposition.

Continuous synthesis of high-entropy alloy nanoparticles by in-flight alloying of elemental metals

High-entropy alloy (HEA) nanoparticles (NPs) exhibit unusual combinations of functional properties. However, their scalable synthesis remains a significant challenge requiring extreme fabrication conditions. Metal salts are often employed as precursors because of their low decomposition temperatures, yet contain potential impurities. Here, we propose an ultrafast (< 100 ms), one-step method that enables the continuous synthesis of HEA NPs directly from elemental metal powders via in-flight alloying. A high-temperature plasma jet ( > 5000 K) is employed for rapid heating/cooling (103 − 105 K s−1), and demonstrates the synthesis of CrFeCoNiMo HEA NPs ( ~ 50 nm) at a high rate approaching 35 g h−1 with a conversion efficiency of 42%. Our thermofluid simulation reveals that the properties of HEA NPs can be tailored by the plasma gas which affects the thermal history of NPs. The HEA NPs demonstrate an excellent light absorption of > 96% over a wide spectrum, representing great potential for photothermal conversion of solar energy at large scales. Our work shows that the thermal plasma process developed could provide a promising route towards industrial scale production of HEA NPs.

Characterization of the Mechanical, Biodegradation, and Morphological Properties of NBR/Biopolymer Blend, Integrated with a Risk Evaluation.

Biopolymer blends have attracted considerable attention in industrial applications due to their notable mechanical properties and biodegradability. This work delves into the innovative combination of butadiene-acrylonitrile (referred to as NBR) with a pectin-based biopolymer (NGP) at a 90:10 mass ratio through a detailed analysis employing mechanical characterization, Fourier transform infrared (FTIR) analysis, thermogravimetric analysis (TGA), and morphology studies using SEM. Additionally, biopolymer's biodegradability under aerobic and anaerobic conditions is tested. The study's findings underscore the superior tensile strength and elongation at break of the NGP/NBR blend in comparison to pure NBR, while also exhibiting a decrease in puncture resistance due to imperfect bonds at the particle-matrix interfaces, necessitating the use of a compatibilizer. In anaerobic conditions, evaluation of biodegradable properties reveals 2% and 12% biodegradability in NBR and NGP/NBR blend, respectively. The degradation properties were also aligned with TGA results highlighting a lower decomposition temperature for NGP. Additionally, this research integrates the application of a conditional value-at-risk (CVaR)-based analysis of the blend's tensile properties to evaluate the uncertainty impact in the experiment. Under risk, a significant enhancement in the tensile performance (by 80%) of the NGP/NBR blend was shown compared to pure NBR. Ultimately, the study shows that adding pectin to the NBR compound amplifies the overall performance of the biopolymer significantly under select criteria.

Low-temperature degradation of waste epoxy resin polymer improved by swelling-assisted pyrolysis

The disposal of waste epoxy resin matrix composite becomes an urgent issue, and pyrolysis is an effective method to decompose the epoxy resin polymer, but the high operating temperature hinders its application. In this study, a swelling-assisted pyrolysis method was proposed for the low-temperature decomposition of epoxy resin. It was found that the degradation ratio of epoxy resin increased from 59.13 % to 79.10 % at 300 °C after the swelling treatment with acetic acid. Compared with traditional pyrolysis, the cracking of epoxy resin was promoted in the swelling-assisted pyrolysis, increasing the yields of pyrolysis gas and oil, as well as enriching the light components in pyrolysis oil and raising the graphite degree of pyrolysis char. Following the characterizations and reactive force field molecular dynamics (ReaxFF-MD) simulation, the key mechanisms of swelling-assisted pyrolysis were determined as the interaction of the enhanced heat transfer and the accelerated ring-open reactions. After the swelling treatment, epoxy resin became porous, improving the heat transfer in the pyrolysis process. Meanwhile, abundant O radicals were generated with the decomposition of acetic acid, accelerating the ring-open reactions of benzene rings. The results could provide promising guidance for the pyrolysis recovery of epoxy resin matrix composites towards the circular economy.

A comparative study of oxidation behavior of Co4Sb12 and Co4Sb10.8Se0.6Te0.6 skutterudite thermoelectric materials fabricated via fast SHS-PPS route

This study examines the oxidation behavior of skutterudite materials fabricated using a rapid self-propagating high-temperature synthesis and pulse plasma sintering route. Pure Co4Sb12 and Co4Sb10.8Se0.6Te0.6 were oxidized in the air at 773 K for up to 500 h. Skutterudites modified with Se and Te had a lower oxidation resistance than that of pure Co4Sb12 and also showed a lower decomposition temperature. This changed the oxidation mechanism, as manifested by the different roles of the Sb2O3 phase during oxide scale formation and the CoSb2-like phase in the modified near-surface region. The unusual mass loss by the Co4Sb10.8Se0.6Te0.6 alloy during the first 100 h of oxidation was also revealed. Despite the evident changes at the surface of the samples, no visible grain growth was noted in both skutterudites. The electrical properties of the samples were also stable.

Research progress on the catalytic and thermal decomposition of ammonium dinitramide (ADN).

Ammonium dinitramide (NH4N(NO3)2, ADN) is regarded as a promising oxidizer due to its low signature and high specific impulse. Generally, ADN undergoes exothermic decomposition above 140 °C accompanied by the byproduct of ammonium nitrate (AN). The inevitable endothermic decomposition of AN decreases the overall heat release, and so there is a need to develop efficient catalysts to guide ADN decomposition along desired pathways with a lower decomposition temperature and higher heat release. A suitable catalyst should be able to withstand the harsh conditions in a thruster to achieve a stable thrust force, which poses a huge obstacle for manufacturing a stable and active catalyst. This review gives a comprehensive summary of the thermal and catalytic decomposition pathways of ADN for the first time, which is expected to deepen the understanding of its reaction mechanism and provide useful guidance for designing prospective catalysts toward efficient ADN decomposition.

Excellent catalytic effect of V2C MXene on dehydrogenation performance of α-AlH3

Lowering the dehydrogenation temperature and maintaining high dehydrogenation capacity are greatly hindering the practical application of α-AlH3 for the hydrogen fuel cell industry. Herein, the layered accordion-like V2C MXene is synthesized and doped into α-AlH3 by mild ball milling. The 1 wt.% V2C-catalyzed α-AlH3 possesses excellent dehydrogenation performance with a low initial decomposition temperature of 70.5 °C and a high hydrogen release capacity of 8.1 wt.%. Furthermore, 7.8 wt.% of hydrogen could be quickly released from α-AlH3-1 wt.% V2C composite within 15 min at 120 °C, with a lower activation energy of 69.5 kJ/mol than that of as-received sample. The excellent dehydrogenation performance is attributed to the high activity of the zero valence V catalyst which is transformed from the multivalent V during ball milling and to promote dissociation and reorganization of hydrogen. This effective approach significantly enhances the dehydrogenation of α-AlH3, providing a hopeful approach for modifying metal hydrides.

In Ukrainian

Thermal destruction of composites of ureaformaldehyde (UPR) and polyester resins (PER) with silicon dioxide nanoparticles having a specific surface area of 280 m2/g, titanium dioxide and titanosilicate with a specific surface area of 40 and 48 m2/g, respectively, when a filler content is no more than 5.0 wt% have been studied. The investigations were performed using The thermally programmed mass spectrometry method with registration of the masses of desorbed atomic fragments in the 10 ‒ 200 m/z range. It was established that during the main polymer mass destruction at 150 ‒ 350 oC, along with low temperature decomposition products, anomalously high thermal resistance of a number of atomic fragments of polymer chains and cross-links are recorded. The atomic composition of destruction fragments and their desorption temperature in the range 400 ‒ 700 oС were determined. It was established that in composites of ureaformaldehyde resin with SiO2 and TiO2 nanoparticles the high temperature resistance of fragments with m/z 27 exhibits due to the formation of strong bonds among the Si and Ti surface sites and the nitrogen atoms of the polymer. Such thermal stability is not realized in resin loading with (Si/Ti)O2 nanoparticles. In composites of polyester resin with silica a high-temperature destruction of oxygen atoms from polyester chains realizes at temperatures of 290 ‒ 400 oC and a low-intensity wide destruction band takes place in the temperature range 400 ‒ 700 oC. In addition, in the temperature range of 400-700 oC cross-links are destroyed with the release of benzene rings and styrene molecules. It was established that anomalously high-temperature desorption is typical for atomic fragments of the polymer structure attached to surface Si and Ti sites through nitrogen or carbon atoms from the polymer structure. Thus, in UPR composites with silicon and titanium oxides, strong chemical nitride bonds of the form Si-N≡C-H and Ti-N≡C-H are formed, which demonstrate anomalously high heat resistance. It is shown that in composites of polyester resin with silicon dioxide nanoparticles, the high-temperature destruction of fragments is due to their desorption from the surface of silicon dioxide particles when breaking their bonds with silicon atoms. Thus, polymer matrices have been determined, in which atomic fragments of the macromolecule, binding to the surface centers of fillers, significantly weaken the thermal destruction of composites due to the formation of strong chemical and coordination bonds.

Ozone-based in-situ reactive extrusion for rapid functionalisation and degradation of low density polyethylene

Improving the hydrophilicity of low density polyethylene (LDPE) expends its use in blends. LDPE melt was rapidly functionalised and degraded by ozone in twin-screw extruder by varying extrusion times from one to seven and temperatures from 160 °C to 240 °C. Abundant oxygen-containing groups, such as carbonyl group (CO) at 1718 cm−1, hydroxyl group (-OH) at 3400 cm−1 and aldehyde group (-CHO) at 1740 cm−1, were generated into ozone treated PE, resulting in improved hydrophilicity. At 200 °C, ozone treated PE exhibited a high melt flow index (21.5 g/10 min) and low complex viscosity modulus due to molecular degradation. Nevertheless, cross-linking occurred at a higher temperature of 240 °C. A higher crystal peak temperature of ozone treated PE at 200 °C was attributed to the introduction of oxygen atoms. The poor thermal stability of ozone treated PE was evidenced by a lower initial decomposition temperature. The oxidation induction time of ozone treated PE at 200 °C declined from 32 min for one extrusion to 12 min for seven extrusions demonstrating a vulnerability of ageing. Increasing the extrusion times gradually enhanced the tensile modulus of the ozone treated PE at 200 °C, while raising the treatment temperature had no effect on the tensile properties. Rapid functionalisation and degradation of LDPE were successfully achieved using ozone in reactive extrusion, thus broadening the applications of ozone treated PE in composites.

Formulating titanium powder feedstocks for metal injection moulding from a clean binder system

Impurity control is paramount in achieving success in titanium metal injection moulding (Ti-MIM), primarily due to Ti being a universal solvent for interstitial elements such as oxygen and carbon. This study developed a clean binder system with a low decomposition temperature based on polypropylene carbonate/polyoxymethylene (PPC/POM). However, due to the poor shape retention of the PPC/POM binder system, polyethylene glycol (PEG) was incorporated to facilitate the formation of a porous network within the compact structure, allowing efficient removal of residual binder for subsequent debinding process. The results reveal that increasing the PEG content leads to a higher binder removal rate, while adding POM enhances shape retention during debinding. The optimal PEG/PPC/POM binder system compositions were identified as 40/48/10% w/w, respectively, offering a higher PEG removal rate and improved shape retention. Lastly, the resultant debound titanium feedstock from this novel binder system showed low impurity contents, complying with ASTM F2989 requirements.

Effect of high-dose electron beam irradiation on thermal decomposition behavior of polytetrafluoroethylene (PTFE)

In this study, we investigated the effect of high-dose (>10.0 MGy) irradiation on polytetrafluoroethylene (PTFE) decomposition in the presence of oxygen. To this end, we analyzed the chemical structures of PTFE residues after irradiation and thermal treatment as well as the outgas components during thermal treatment at 50 °C intervals. Thermogravimetric analyses indicated that the residual PTFE powder exhibited an initial decomposition (5% weight loss) at 159 °C, which is 365 °C lower than that of the original unirradiated sample. The initial decomposition temperature decreased at up to 5 MGy and gradually leveled off at above 140 °C. Fourier transform infrared (FT-IR) spectroscopy analysis of the residual PTFE powders indicated that the contents of thermal decomposition at lower temperature ranges were qualitatively related to the extent of the formation of oxidizable PTFE components, such as carbonyl groups. The formation of these components increased as the absorbed doses increased. The oxidized components gradually decreased with increasing thermal treatment temperature and tended to disappear at 470 °C. This demonstrated the effect of the oxidized compounds in the irradiated PTFE on lower temperature decomposition. The analysis of the gas components resulting from the thermal decomposition of the PTFE residuals revealed more detailed chemical information concerning the oxidative components of the irradiated PTFE. At temperatures below 420 °C, approximately 30% of the PTFE residue underwent pyrolysis to yield oxidized fluorocarbon products (CxFyOz) and further decomposed products (CO2). The remaining 70% of the residue thermally decomposed at temperatures above 420 °C, yielding monomer-related products such as C2F4, C3F6, and C4F8. These were identical to the gas products resulting from the thermal degradation of the original PTFE in the same temperature range. These results are indicative of the possibility of recycling and reusing fluorocarbons during irradiation.

Performance characteristics of nitramine‐based gun propellants with TEGDN as energetic plasticizer

AbstractThis study mainly explored the performance characteristics of nitramine‐based (NB) gun propellants using TEGDN as an energetic plasticizer by experimental method. Three series of NB gun propellant samples with RDX, HMX or CL‐20 were prepared referring to the formulation of JA2 gun propellant. Their thermochemical characteristics, explosion heat, chemical stability and compatibility, impact, friction and electrostatic spark sensitivities, and compressive strength were determined by various instruments. The experimental results indicated that the NB gun propellant samples with RDX have lower decomposition temperature, and those with CL‐20 have higher thermogravimetric loss. Three series of NB gun propellant samples have good chemical stability and compatibility, and their explosion heat is close to that of JA2 gun propellant, but their sensitivity is lower than that of JA2 gun propellant. The maximum stress of three series of NB gun propellant samples decreases with increasing cyclic nitramine (RDX, HMX or CL‐20) content, and their compressive strength is better than that of JA2 gun propellant.