Nitrate Esters Research Articles

Towards Investigating the Effect of Ammonium Nitrate on the Characteristics and Thermal Decomposition Behavior of Energetic Double Base NC/DEGDN Composite.

This research work aimed to elaborate on a new modified double-base propellant containing nitrocellulose (NC), ammonium nitrate (AN), and diethylene glycol dinitrate (DEGDN). The developed AN/NC-DEGDN formulation was successfully obtained through a casting process and fully characterized in terms of its chemical structure, morphological features, and thermal behavior. Beforehand, theoretical calculation by the CEA-NASA program was applied to select the optimal composition of the formulation. Experimental findings demonstrated the homogenous dispersion of AN oxidizer in the NC-DEGDN matrix without alteration of their molecular structures. The catalytic influence of AN on the thermal decomposition behavior of NC-DEGDN film was also elucidated by thermal analyses. When AN was incorporated into the formulation, the decomposition peak temperatures for the different decomposition processes were shifted toward lower temperatures, while the total enthalpy of decomposition increased by around 1272.24 J/g. In addition, the kinetics of the thermal decomposition of the developed modified double base propellant were investigated using DSC results coupled with model kinetic approaches. It was found that the addition of AN decreases the activation energy of nitrate esters from 134.5 kJ/mol to 118.84 kJ/mol, providing evidence for its excellent catalytic effect. Overall, this investigation could serve as a reference for developing future generation of modified double-base propellants.

Identification of the Degradation Products from α‐Tocopherol Used as Stabiliser in “Green” Propellants through its Lifetime

AbstractStabilisers are added to gun and rocket propellants to react with species responsible for nitrate ester degradation during storage. The degradation products can be toxic and therefore harmful. There is a need to replace such stabilisers by “green” molecules and to study their degradation patterns through ageing. Propellant powders must remain chemically stable for a minimum of ten years when stored at temperatures equivalent to 25 °C [1]. α‐Tocopherol is a natural product that has been known for decades in other fields (Vitamin E) such as the pharmaceutical, food and cosmetics industries. It can act as a ‘green’ stabiliser” for smokeless powders because its heat flow is stable over time. In this paper, we characterise its stabilisation mechanism by identifying its main degradation products that could form within the propellant in an oxidising environment and in the presence of nitric acid. Liquid chromatography (LC) and gas chromatography (GC) separations are performed in order to dissociate the compounds formed during ageing. Compounds are then analysed by APCI‐timsTOF to obtain the molecular ion masses and then perform fragmentation spectra (MS/MS) to characterise their structure. In addition, using preparative HPLC‐UV, the degradation products are collected and analysed by NMR, with the aim of identifying the molecules. These identification methods help to unravel the stabilisation mechanism under accelerated ageing conditions. A time‐related fluctuation of the degradation products amounts is also observed, which indicates that the decomposition products also have a stabilisation effect. The three major α‐tocopherol degradation products are identified as: 2,3‐epoxy‐α‐tocopherylquinone, 5,6‐epoxy‐α‐tocopherylquinone and α‐tocored.

Design, Synthesis, and Investigation of Novel Nitric Oxide (NO)-Releasing Aromatic Aldehydes as Drug Candidates for the Treatment of Sickle Cell Disease.

Sickle cell disease (SCD) is caused by a single-point mutation, and the ensuing deoxygenation-induced polymerization of sickle hemoglobin (HbS), and reduction in bioavailability of vascular nitric oxide (NO), contribute to the pathogenesis of the disease. In a proof-of-concept study, we successfully incorporated nitrate ester groups onto two previously studied potent antisickling aromatic aldehydes, TD7 and VZHE039, to form TD7-NO and VZHE039-NO hybrids, respectively. These compounds are stable in buffer but demonstrated the expected release of NO in whole blood in vitro and in mice. The more promising VZHE039-NO retained the functional and antisickling activities of the parent VZHE039 molecule. Moreover, VZHE039-NO, unlike VZHE039, significantly attenuated RBC adhesion to laminin, suggesting this compound has potential in vivo RBC anti-adhesion properties relevant to vaso-occlusive events. Crystallographic studies show that, as with VZHE039, VZHE039-NO also binds to liganded Hb to make similar protein interactions. The knowledge gained during these investigations provides a unique opportunity to generate a superior candidate drug in SCD with enhanced benefits.

Modeling Photolytic Decomposition of Energetically Functionalized Dodecanes.

The photolytic stability of explosives and energetic functional groups is of importance for those who regularly handle or are exposed to explosives in typical environmental conditions. This study models the photolytic degradation of dodecane substituted with various energetic functional groups: azide, nitro, nitrate ester, and nitramine. For the studied molecules, it was found that excitons localize on the energetic functional group, no matter where they were initially formed, and thus, the predominant degradation pathway involves the degradation of the energetic functional group. The relative trends for both 4 and 8 eV excitation energies followed with what is expected from the relative stability of the energetic functional groups to thermal and sub-shock degradation. The one notable exception was the azide functional group; more work should be done to further understand the photolytic effects on the azide functional group.

Identifying the Molecular Properties that Drive Explosive Sensitivity in a Series of Nitrate Esters.

Energetic materials undergo hundreds of chemical reactions during exothermic runaway, generally beginning with the breaking of the weakest chemical bond, the “trigger linkage.” Herein we report the syntheses of a series of pentaerythritol tetranitrate (PETN) derivatives in which the energetic nitrate ester groups are systematically substituted by hydroxyl groups. Because all the PETN derivatives have the same nitrate ester-based trigger linkages, quantum molecular dynamics (QMD) simulations show very similar Arrhenius kinetics for the first reactions. However, handling sensitivity testing conducted using drop weight impact indicates that sensitivity decreases precipitously as nitrate esters are replaced by hydroxyl groups. These experimental results are supported by QMD simulations that show systematic decreases in the final temperatures of the products and the energy release as the nitrate ester functional groups are removed. To better interpret these results, we derive a simple model based only on the specific enthalpy of explosion and the kinetics of trigger linkage rupture that accounts qualitatively for the decrease in sensitivity as nitrate ester groups are removed.

Chemistry and Bioactivity of the Deep-Water Antarctic Octocoral Alcyonium sp.

Chemical investigation of an Antarctic deep-water octocoral has led to the isolation of four new compounds, including three illudalane sesquiterpenoids (1–3) related to the alcyopterosins, a highly oxidized steroid, alcyosterone (5), and five known alcyopterosins (4, 6–9). The structures were established by extensive 1D and 2D NMR analyses, while 9 was verified by XRD. Alcyopterosins are unusual for their nitrate ester functionalization and have been characterized with cytotoxicity related to their DNA binding properties. Alcyopterosins V (3) and E (4) demonstrated single-digit micromolar activity against Clostridium difficile, an intestinal bacterium capable of causing severe diarrhea that is increasingly associated with drug resistance. Alcyosterone (5) and several alcyopterosins were similarly potent against the protist Leishmania donovani, the causative agent of leishmaniasis, a disfiguring disease that can be fatal if not treated. While the alcyopterosin family of sesquiterpenes is known for mild cytotoxicity, the observed activity against C. difficile and L. donovani is selective for the infectious agents.

The influence of solvent selection on nitrocellulose-based, perchlorate-free red-and green-light illuminants

ABSTRACT Nitrocellulose (NC) has been used since the late 1800ʹs in numerous energetic formulations; however, the effect of processing agents (solvents, etc.) on performance has not been thoroughly detailed. For illuminate applications, this is critical as spectral purity and dominant wavelength must meet specifications. In this effort, six processing agents (water, ethanol (EtOH), isopropyl alcohol (IPA), ethyl acetate (EtAc), acetone, and tetrahydrofuran (THF)) are evaluated and the effect they have on the NC fibers and subsequent performance is detailed. XRD and FTIR analysis indicates that the choice of processing agent directly affects the molecular integrity of the NC fibers due to the inhibition of NO2 bonds as well as freeing of hydrogen bonds between polymer chains during solubilization. Time-step FTIR analysis indicated that the weak nitrate ester bond (RCH2-ONO2) is targeted when processed in tetrahydrofuran, ethyl acetate, or acetone, and if heavy solvent interaction occurs, can lead to the autocatalytic decomposition of NC, when heat treated at 110°C. Spectral performance is detrimentally impacted as a result of such interactions. While all six processing agents for red-light illuminant formulations met the military requirements (i.e., spectral purity and wavelength), only ethanol and isopropyl alcohol processed formulations met the military required wavelength of 540 ± 20 nm for green-light illuminants. The IPA processed formulations exhibited the best results with spectral purity values of 69.0% and 94.8% for green and red-light illuminants, respectively.

Sustained Release of Nitric Oxide and Cascade Generation of Reactive Nitrogen/Oxygen Species via an Injectable Hydrogel for Tumor Synergistic Therapy

AbstractReactive nitrogen species (RNS) generated via the reaction of nitric oxide (NO) with reactive oxygen species (ROS) are more lethal than ROS, and thus RNS‐mediated therapy has great potential in cancer treatment, yet it is still largely unexploited. Herein, a novel, injectable and NO‐releasing hydrogel (NO‐Gel) composed of α‐(nitrate ester) acetic acid‐modified amphiphilic copolymers is developed. To further convert released NO to RNS, glutathione (GSH)‐sensitive CuCys nanoparticles (NPs) and β‐lapachone (Lapa) are co‐loaded into the NO‐Gel. This hydrogel system possesses a temperature‐induced sol‐gel transition and can continuously liberate Lapa, CuCys NPs, and NO in vitro for up to 3 weeks. The sustained supply of Lapa can efficiently boost hydrogen peroxide (H2O2) concentration in cancer cells, and intracellular GSH can induce the rapid release of NO and the reduction of CuCys NPs. With elevating H2O2 levels and producing highly reactive Cu(I), the Cu(I)‐catalyzed Fenton‐like reaction is dramatically enhanced, resulting in the generation of abundant hydroxyl radicals (·OH), and the subsequent cascade reactions among ·OH, H2O2, and NO cause more lethal RNS pool. After a single peritumoral injection of the hydrogel system, the cascade generation of ROS and RNS plus the substantial depletion of GSH can significantly suppress tumor growth.

Molecular dynamic simulations of modeling aluminum-based composite nanoparticle in liquid Cellulose dinitrate decamer sol

Aluminum nanoparticle (ANP) in liquid Cellulose dinitrate decamer sol was investigated by ReaxFF molecular dynamics simulations. The mechanism of nitrocellulose (NC) single chain adsorption was researched as a chemisorption process. New Al–O bonds are formed by dehydrogenation and denitrification of the nitrate ester groups. The adsorbed part of the NC chain drags other parts to the surface as a horizontal adsorption state. We also simulated the processes of liquid Cellulose dinitrate decamer sol (ethanol, diethyl ether, and NC three components) coating the ANPs at different temperatures. The results indicate that the organic coating near surface is mainly consisted of ethanol and diethyl ether molecules. The NC chains are adsorbed on the ANPs surface in two states, including the horizontal adsorption or the nearly vertical adsorption. Heating can increase the coating rate without significantly changing the composition of the coating. Finally, the oxidation simulation shows that the organic layer can maintain good stability and oxidation resistance.

Novel purine analogues regulate IL-1β release via inhibition of JAK activity in human aortic smooth muscle cells

Purine analogues bearing a nitrate ester motif were previously discovered as cardioprotective and anti-inflammatory agents, but the anti-inflammatory mechanism remains to be established. We therefore investigated the anti-inflammatory effect of two purine analogues, MK118 bearing a nitrate ester moiety and the methyl-substituted analogue MK196 in Aortic Smooth Muscle Cells (AoSMCs), with emphasis on IL-1β release. The AoSMCs were stimulated with LPS with or without purine analogue, followed by ELISA, Olink proteomics, Western blot and real time PCR of NLRP3 inflammasome components. Both purine analogues inhibited the release of proteins involved in inflammation, such as TRAIL, CCL4, CSF1 and IL-1β in AoSMCs, as well as intracellular gene and protein expression of IL-1β and NLRP3 inflammasome components. MK196, but not MK118, also inhibited the LPS-induced release of IL-7, CXCL10, PD-L1, FLT3L and CCL20. We also showed that MK118 and possibly MK196 act via inhibition of JAKs. In silico studies showed that the purine moiety is a competent hinge binding motif and that the purine-piperazine scaffold is well accommodated in the lipophilic groove of JAK1-3. Both compounds establish interactions with catalytic amino acids in the active site of JAK1-3 and the terminal nitrate ester of MK118 was revealed as a promising pharmacophore.Our data suggest that MK118 and MK196 inhibit the release of proinflammatory proteins in AoSMCs, and targets JAK1-3 activation. Purine analogues also inhibit the expression of NLRP3 inflammasome genes and proteins and may in the future be evaluated for anti-inflammatory aspects on inflammatory diseases.

Electronegativity at the Shock Front

AbstractIn this work, a scale for pressure‐adapted atomic electronegativity is used to make general predictions of bond polarity in H‐, C‐, N‐ and O‐based compounds experiencing shock conditions. The qualitative picture that emerges is one of increasing polarity of several bonds common in energetic materials. The general predictions made are compared to, and found to support, claims of ionic decomposition routes in compressed nitromethane and nitrate esters at high pressure. Changing electronegativity is also suggested as a factor driving the ionic disproportionation of various molecular phases with compression. Calculations using the eXtreme‐Pressure Polarizable Continuum Model (XP‐PCM) predict increasing energy differences between ground and excited states in non‐bonded H, C, N, and O atoms as a function of pressure. This data enables for a discussion on the reliability of electronegativity‐based rationales at more extreme thermodynamic conditions.

Narrow-band infrared radiation characteristics of rocket exhaust plume by using correction function related to thermodynamic state

Modeling of plume infrared radiation requires the accurate calculation of gas radiation properties of the plume non-uniform flow field. Aiming at the problem that the Curtis-Godson approximation (CGA) method can give the exact result in the limits of weak lines and strong lines, but overestimates the absorption of the optical intermediates path. This study develops an accurate model to study the infrared radiation of rocket plume. This model calculates narrow-band radiation properties using an equivalent half-width corrected by a correction function, which relates to the thermodynamic state of the no-uniform plume and is followed by radiative transfer calculations. Several Lorentz single lines were adopted to evaluate this correction function by the equivalent width of a fictitious non-uniform gas column, results showed high accuracy, especially at optical intermediates. Simulation of plume reaction flow was implemented by a refined 11-species, 17-reaction chemistry scheme, which can describe the afterburning between the multi-component fuel injected from the nozzle and ambient air. Then, adopting the temperature, pressure and radiating species distribution of the plume flow field, the model can predict accurate spectra that fit the experimental spectrometer data well. Finally, the effects of propellant formulation and flight conditions on plume infrared radiation were investigated: (a) hydroxyl-terminated polybutadiene (HTPB) and nitrate ester plasticized polyether (NEPE); (b) flight altitude; (c) flight Mach number. Results show that the composition of the propellant has a significant effect on the plume afterburning, NEPE plume afterburning effect is stronger, and the total radiation intensity is 61.5% higher than HTPB in 1.5–6.0 μm. The increase of flight altitude weakens the radiation, while due to the expansion of the radiant area, the spectral radiation intensity increases significantly. With the increase of Mach number, the band intensity decreases exponentially, and the plume structure gradually develops into a slender shape, the radiation decreases significantly. The research has significance for the application of target early warning, detection and identification.

Molecular simulation study of the stabilization process of NEPE propellant

In this reported study, the density functional theory (DFT) was used at the (U)B3LYP/6-311G(d,p) level to investigate the stabilization process of the nitrate ester plasticized polyether propellant (NEPE). Molecular simulations were conducted of the reaction that generates NO2, the autocatalytic and aging reaction triggered by the NO2, and the nitrogen dioxide absorption reaction of the stabilizers during the propellent stabilization process. These simulations were derived using the transition-state theory (TST) and variational transition-state theory (VTST). The simulation results suggested that the stabilization of the NEPE propellant consisted of three stages. First, heat and NO2 were generated during the denitrification reaction of nitroglycerine (NG) and 1,2,4-butanetriol trinitrate(BTTN) in the NEPE propellant. Second, nitroso products were generated by the reactions of N-Methyl-4-nitroaniline (MNA) and 2-nitrodiphenylamine (2NDPA) with NO2. Third, the stabilizers were exhausted and the autocatalytic reaction of NG and BTTN and the aging reaction of polyethylene glycol (PEG) were triggered by the heat and NO2 generated in the first stage. By comparing the energy barriers of the various reactions, it was found that the NO2 generated from the denitrification reaction significantly reduced the reaction energy barrier to 105.56–126.32 kJ/mol, also increased the reaction rate constant, and decreased the thermal stability and energetic properties of the NEPE propellant. In addition, the NO2 also weakened the mechanical properties of the NEPE propellant by attacking the –CH2 groups and the O atoms in the PEG molecular chain. The energy barriers of the reactions of MNA and 2NDPA with NO2 (94.61–133.61 kJ/mol) were lower than those of the autocatalytic and decomposition reactions of NG, BTTN, and the aging reactions of PEG (160.30–279.46 kJ/mol). This indicated that, by eliminating NO2, the stabilizer in the NEPE propellant can effectively prevent NO2 from reacting with the NG, BTTN, and PEG in the NEPE propellant. Consequently, this would help maintain the energy and mechanical properties of the NEPE propellant, thereby improving its thermal stability.

Mechanical behavior and constitutive model of NEPE solid propellant in finite deformation

Nitrate ester plasticized polyether (NEPE) solid propellant was widely used in carrier rocket and guided missiles, owing to its excellent mechanical properties, high specific impulse and good performance of low temperature storage. The material of NEPE suffered from thermal cycle, high pressure impulse and vibration during service life. Thus, the mechanical properties of NEPE had important implications for the safety of structure and service life. Experimental results indicated that the material presents significant time-dependence and nonlinear characteristics. In order to clarify the damage mechanism of NEPE solid propellant, the mesostructure evolution was investigated with the 3D in-situ observations by using synchrotron radiation computed tomography (SR-CT). The voids initiated at the interface between matrix and particles and propagated along the loading direction. With the increasing of loading, matrix breaking, particles breaking and debonded particles were observed in the near-surface regions. Furthermore, a visco-hyperelastic constitutive model coupling damage was proposed to describe the mechanical behavior of NEPE under finite deformation. The constitutive model provides a good simulation with experimental results, which is meaningful to the structure integrity assessment of NEPE solid propellant.

Principal Component Analysis of FTIR Data to Accurately Assess the Real/Equivalent In‐Service‐Times of Homogenous Solid Propellant

AbstractThis study was devoted to setting up new methodologies for an accurate assessment of both real and equivalent in‐service‐times (RIST/EIST) of homogenous solid propellants (HSP) through a combination of principal component analysis (PCA) and Fourier transform infrared (FTIR) spectroscopy. Four double‐base rocket propellants (DBRP) have been artificially aged at T=338.65 K for 4 months with sampling every 20 days. FTIR showed that the homolytic scission of the O‐NO2 bonds and the hydrocarbon chains of the nitrate esters are the main processes occurring during the chemical decomposition. The scatter plot from PCA of FTIR spectra shows that over 93 % of the variance was described by the first principal component. Moreover, the loading plot designated the three characteristic FTIR bands from the nitro (NO2) group as the most influenced by aging. A new PCA/FTIR experimental way was set to accurately assess the RIST of HSPs. The relative deviation associated with the RIST evaluated by the present procedure and those from the PCA/VST experimental way, recently developed, was found to range from 4.0 % to 6.7 %. Subsequently, a PCA/FTIR prediction model of the EIST is established. The predictions present a relative deviation of less than 7.1 % compared to the recent PCA/VST model. The accuracy of the model was further confirmed using similar DBRPs artificially aged for 6, 8, 10, and 12 months. The relative variation between the RIST provided by the PCA/FTIR procedure and the prediction model was found less than 5 %, thus confirming the highest accuracy of such combination.

Rapid and straight forward mass spectrometric determination of nitrocellulose in smokeless powder by DART-Q-ToF-MS/MS

Smokeless powders (SPs) are a group of low-explosives primarily used as propellant in various munitions and are frequently employed as explosive charges in bombings and terrorist attacks. However, the reliable determination of nitrocellulose (NC), one of the main components of SP remains an analytical challenge, especially in post-blast residues. While highly desirable because of its selectivity, the mass spectrometric (MS) detection of NC is hindered by its polymeric nature and broadly distributed molecular weight, as well as its poor ionizability in many common MS ion-sources. Direct Analysis in Real Time (DART) – MS allows for the rapid and simple analysis of samples and poses a means of circumventing the problems associated with detection of NC. Analytes in DART readily form adducts, which enables the straight-forward detection of nitrate esters such as glucose trinitrate and cellobiose hexanitrate, the respective monomeric and dimeric subunit of NC, and obviates the need for prior derivatization. Therefore, this method is well suited to rapidly and reliably determine the presence of NC in bulk, as well as consumed SP, as could be shown in this proof-of-concept study for a set of three single-base SPs.

Examining the Effect of Trimethylol Propane Crosslinker on Butanetriol Trinitrate Plasticized Polycaprolactone Polymer Networks of Propellant Binder System

AbstractThe knowledge of polymer network characteristics is important to tune the properties of advanced energetic propellants based on nitrate ester plasticized polyol binder system. In this article, plasticized polyurethane networks of polycaprolactone (PCP) and hydroxyl‐terminated polybutadiene (HTPB) with different crosslinker content [0 to 0.20 parts] at various stoichiometric ratios (r‐value) [0.8 to 1.0] were studied. Five numbers of polyurethane networks of 1,2,4‐butanediol trinitrate (BTTN) plasticised PCP were formulated at each r value 0.8, 0.9 and 1.0 using 0, 0.05, 0.10, 0.15 and 0.20 parts of trimethylolpropane (TMP) crosslinker. Similarly, five numbers of dioctyl adipate (DOA) plasticized HTPB based polyurethane networks were formulated at r‐value of 0.8. FT‐IR spectra of these polyurethane networks (PUNs) were recorded for functional group identification. Stress‐strain behavior of PUNs was studied for understanding the effect of TMP content and r value on mechanical properties. Hard segment content of PUNs were calculated and its influence on network characteristics and mechanical properties was evaluated. CLD values (ν) increased with increase of hard segment content of PUN and the values quantified by different approaches followed the trend νe (by solvent swelling method) > νne2(by Initial modulus method)>νne1 (by Mooney Rivlin method).

Chemical Evaluation and Performance Characterization of Pentaerythritol Tetranitrate (PETN) under Melt Conditions.

Pentaerythritol tetranitrate (PETN) is a nitrate ester explosive commonly used in commercial detonators. Although its degradation properties have been studied extensively, very little information has been collected on its thermal stability in the molten state due to the fact that its melting point is only ∼20 °C below its onset of decomposition. Furthermore, studies that have been performed on PETN thermal degradation often do not fully characterize or quantify the decomposition products. In this study, we heat PETN to melt temperatures and identify thermal decomposition products, morphology changes, and mass loss by ultrahigh-pressure liquid chromatography coupled to quadrupole time of flight mass spectrometry, scanning electron microscopy, nuclear magnetic resonance spectroscopy, and differential scanning calorimetry. For the first time, we quantify several decomposition products using independently prepared standards and establish the resulting melting point depression after the first melt. We also estimate the amount of decomposition relative to sublimation that we measure through gas evolution and evaluate the performance behavior of the molten material in commercial detonator configurations.

Forensic science deals with safety armour during warfare explosives

Forensic analysis of explosives includes analysis of post-explosion residues, and detection and identification of traces of explosives on suspects’ hands, on clothing, and on other related items. Preliminary field tests may be used for screening the debris on the explosion site. They include commercially available explosive vapor detectors and chemical color tests. Like post-explosion residues, personal items suspected to contain traces of explosives and hand-swabs, are often heavily contaminated. It is therefore of major importance that the analytical procedures have to include good screening, clean-up, and extraction methods. The main explosives dealt with in this chapter include nitroaromatic explosives, such as 2,4,6-trinitrotoluene (TNT) and 2,4,6, N-tetranitro-N-methyl aniline (tetryl), nitrate esters, such as ethylene glycol dinitrate (EGDN), glycerol trinitrate (nitroglycerin, NG), and pentaerythritol tetranitrate (PETN), and nitramine explosives, such as 1,3,5- trinitro-1,3,5-triazacyclohexane, (RDX) and 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX), as well as mixtures containing one or more of these explosives. Additional explosives include triacetone triperoxide (TATP) and ammonium nitrate (AN), NH4NO3.

Study on the Cocrystallization Mechanism of CL-20/HMX in a Propellant Aging Process through Theoretical Calculations and Experiments.

Energetic materials undergo physical and chemical aging due to environmental effects, resulting in the degradation of safety and detonation performances. Therefore, studying the aging performance of energetic materials is of great importance for the efficient application of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20)-based solid propellants. In this paper, XRD and FTIR of the CL-20-based propellant and CL-20/1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX)-based propellant samples showed CL-20/HMX cocrystal formation according to appearance of new peaks. SEM and EDS analyses showed that pores and dehumidification in the propellant occurred with the cocrystallization of CL-20 and HMX during the aging process. Furthermore, molecular dynamics simulation was used to predict the crystal transformation of the CL-20- and HMX-based propellant under a long-term storage process. The stability of ε-CL-20 was obtained by analyzing the crystal transformation rate. The binding energy, radial distribution function between CL-20 and HMX, as well as mechanical properties of the CL-20/HMX cocrystal and the mixture were calculated to reveal the stronger binding between CL-20 and HMX in the cocrystal. Meanwhile, the inducer effect of a nitrate ester during the cocrystallization process was analyzed. The theoretical calculation shows that during aging, ε-CL-20 tends to exist stably, while CL-20/HMX tends to form cocrystals because of the strong bond. The present work on the transformation and cocrystallization of CL-20 and HMX during long-term storage is beneficial for understanding the degradation mechanism of the propellant performances, facilitating safe storage and life evaluation of propellants.