Design and Synthesis of a Series of CL-20 Cocrystals: Six-Membered Symmetrical N-Heterocyclic Compounds as Effective Coformers

Crystal Growth & Design, Год журнала: 2019, Номер 19(5), С. 2779 - 2784

Опубликована: Апрель 10, 2019

Cocrystallization of energetic compounds has recently been considered as an effective method to adjust the properties through selection coformers, particularly improve detonation and reduce mechanical sensitivity CL-20. In this research, a reliable promising design strategy synthesize CL-20-based cocrystals was presented, where (i) coformer should show local structural similarity CL-20, i.e., five- or six-membered symmetric heterocycles, (ii) molecular structure contain electron-donating groups. order verify adaptability strategy, pyrazine, 2,6-dimethoxy-3,5-dinitropyrazine, 2,5-dimethylpyrazine were selected templates symmetrical N-heterocyclic for cocrystallization with Fortunately, on basis results experiments crystal analysis, three successfully cocrystallized Moreover, two same components different stoichiometric ratios formed by pyrazine addition, designed cocrystals, including thermal stability, properties, sensitivities, also studied in detail. CL-20 aforementioned coformers demonstrates appropriateness coformers. light finding, safety can be modulated employing suitable

Язык: Английский

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Interfacial reinforcement of core-shell HMX@energetic polymer composites featuring enhanced thermal and safety performance

Defence Technology, Год журнала: 2023, Номер 31, С. 387 - 399

Опубликована: Фев. 9, 2023

The weak interface interaction and solid-solid phase transition have long been a conundrum for 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane (HMX)-based polymer-bonded explosives (PBX). A two-step strategy that involves the pretreatment of HMX to endow –OH groups on surface via polyalcohol bonding agent modification in situ coating with nitrate ester-containing polymer, was proposed address problem. Two types energetic polyether—glycidyl azide polymer (GAP) modified GAP (GNP) were grafted onto crystal based isocyanate addition reaction bridged through neutral polymeric (NPBA) layer. morphology structure HMX-based composites characterized detail core-shell validated. polymers obviously enhanced adhesion force between crystals fluoropolymer (F2314) binder. Due interfacial reinforcement among components, two exhibited remarkable increment peak temperature by 10.2°C 19.6°C no more than 1.5% shell content, respectively. Furthermore, impact friction sensitivity decreased significantly as result barrier produced polymers. These findings will enhance future prospects design aiming solve safety concerns.

Язык: Английский

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Enhanced Thermal Decomposition and Safety of Spherical CL-20@MOF-199 Composites via Micro-Nanostructured Self-Assembly Regulation

ACS Applied Materials & Interfaces, Год журнала: 2023, Номер 15(35), С. 41850 - 41860

Опубликована: Авг. 23, 2023

The characteristics of high burning rate, energy output, and low pressure exponent have always been the focus development in field composite solid rocket propellants. In this paper, a metal–organic framework (MOF-199) compound is introduced to prepare micro-nanospherical CL-20@MOF-199 composites via spray-drying self-assembly technique reach above goals. MOF-199, which acts as an attractive combustion catalyst safety regulator, uniformly coated on surface CL-20 with close interface contact between particles, effectively accelerating thermal decomposition ensuring performance. average noncovalent interaction (aNCI) analysis illustrates that there are strong C–H···O hydrogen bonds van der Waals MOF-199 molecules, greatly enhancing effect interparticle assembly. effects different contents thermal, safety, properties were discussed. demonstrates has significant catalytic CL-20, advanced peak temperature 14.2 °C reduced activation barrier 34.2 kJ·mol–1, mainly benefitting from more exposed active sites contact. addition, exhibit decreased mechanical sensitivity (IS: 21–40 cm, FS: 80–240 N) excellent This work clearly both superior good buffer for it opens new potential further applications

Язык: Английский

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Comparative Studies of Synthesis, Performance, and Applications of Recently Developed CL-20 Based Co-crystals

Crystal Growth & Design, Год журнала: 2023, Номер 23(9), С. 6974 - 6987

Опубликована: Авг. 19, 2023

Owing to promising characteristics including a high heat of formation (100 kcal·mol–1), density (2.04 g·cm–3), and powerful explosive nature (14–20% more potent than 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX)), the hollow cage-type molecular structure polycyclic nitramine 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (HNIW/CL-20) has recently attained significant attention from scientists. Its sensitivity toward mechanical stimuli raises safety concerns. The safety–power contradiction high-energy explosives can be alleviated certain extent via co-crystallization method. It is possible modify properties energetic materials such as melting decomposition point, density, detonation (detonation velocity pressure), sensitivities (friction impact) by forming new chemical composition new/existing molecules through noncovalent interactions (π–π stacking, hydrogen bonds, van der Waals forces). Energetic co-crystals have been developed various approaches solvent evaporation, solvent/nonsolvent, grinding, slurry, resonant acoustic mixing, etc. This Review highlights an interesting overview HNIW/CL-20 based co-crystals, their synthetic methods, intermolecular interactions, physicochemical properties. Moreover, applications, existing problems, challenges for future work on CL-20-based are also discussed.

Язык: Английский

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Novel approach for preparation of the energy-safety balanced cocrystals of attractive nitramines via coagglomeration

FirePhysChem, Год журнала: 2024, Номер 4(4), С. 283 - 294

Опубликована: Март 6, 2024

Co-agglomeration unique crystal engineering approach; in which the co-precipitated micro-particles of nitramines with other energetic materials co-agglomerated by slurry method; to modify properties attractive like CL20, HMX, BCHMX, and RDX etc. The interesting structural modifications newly prepared crystals (CACs) one are discussed here. There notable variations morphologies packing crystals, including key relatively high density, melting point, impact sensitivity, detonation properties. These CACs overwhelming majority showing co-crystals. Apart from these aspects, co-agglomeration provides a huge opportunity tune performance existing is easy scale-up for industrial level. preliminary results also suggest that chemical factors involved preparation have tremendous improvements than conventional crystallization. With technological optimization this method can be employable scale production.

Язык: Английский

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