In addition to the three classical methods for adjusting the performance of energetic complexes, in order to explore the influence of different bonding types on the performance of energetic materials, we designed ionic salts PZCA•HClO 4 (3) and ECPs [Ag(PZCA)ClO 4 ] n (4) with PZCA(1H-pyrazole-4carbohydrazide) as the ligand. They use the same ligands and oxidizing acids and also have the same N/O number. On the basis of their structures and compositions confirmed by infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction, the characterization of physical and chemical properties shows that 4 has better thermal decomposition behavior (ΔT = 30 °C), more suitable mechanical sensitivity (IS = 5 J, FS = 9 N), and more outstanding initiation performance. After studying the decomposition mechanism, we find that different types of bonds (H bond or coordination covalent bond) lead to different decomposition mechanisms (redox reaction or free radical reaction) and, finally, show great differences in explosive properties.
The energetic performance of hexanitrohexaazaisowurtzitane (CL-20) was modulated with two energetic coordination polymers (ECPs), [Cu(ANQ) 2 (NO 3 ) 2 ] and [Ni(CHZ) 3 ](ClO 4 ) 2 , in this study by a two-step method. First, tannic acid polymerized in situ on the surface of CL-20 crystals. Then, [Cu(ANQ) 2 (NO 3 ) 2 ] and [Ni(CHZ) 3 ](ClO 4 ) 2 were hydrothermally formed on the surface of CL-20/TA, respectively. Explosion performance tests show that the impact sensitivity of the coated structure CL-20/TA/[Cu(ANQ) 2 (NO 3 ) 2 ] is 58% less than that of CL-20 with no energy decrease. On the other hand, CL-20/TA/[Ni(CHZ) 3 ](ClO 4 ) 2 can be initiated by a low laser energy of 107.3 mJ (Nd:YAG, 1064 nm, 6.5 ns pulse width), whereas CL-20 cannot be initiated by even 4000 mJ laser energy. This study shows that it is feasible to modify the performance of CL-20 by introducing energetic CPs with certain properties, like high energy insensitive, laser-sensitive, etc., which could be a prospective method for designing high energy insensitive energetic materials in the future.
Guided by structural chemistry and crystallization chemistry, two coordination polymers Cu(AOCA) 2 (NO 3 ) 2 (ECPs-1) and [Cu(PZCA)(NO 3 )](NO 3 ) (ECPs-2) were prepared by reacting 4-amino-1,2,5-oxadiazole-3-carbohydrazide (AOCA) and pyrazole-4-carbohydrazide (PZCA) with Cu(NO 3 ) 2 , respectively, and their structures and properties were characterized. Single-crystal XRD proved that ECPs-1 was a solvent-free 0D structure, while ECPs-2 was a one-dimensional (1D) structure containing coordinated water. TG-DSC tests manifested that ECPs-1 had better thermal stability (T ted = 159 °C), while ECPs-2 had a better decomposition rate (ΔT = 25 °C). In addition, their safety was evaluated by measuring their combustion heat and mechanical sensitivity. Using only ECPs-1 and ECPs-2 as the main components of the pyrotechnic agents, the combustion performance and flame color effect were studied. The results proved that they both have the potential to be used as pyrotechnics, and the purity of ECPs-1 is higher, reaching 79%.
The requirements for high energy and green primary explosives are more and more stringent because of the rising demand in the application of micro initiation explosive devices. Four new energetic compounds with powerful initiation ability are reported and their performances are experimentally proven as designed, including non‐perovskites ([H2DABCO](H4IO6)2·2H2O, named TDPI‐0) and perovskitoid energetic materials (PEMs) ([H2DABCO][M(IO4)3]; DABCO=1,4‐Diazabicyclo[2.2.2]octane, M=Na+, K+, and NH4+ for TDPI‐1, ‐2, and ‐4, respectively). The tolerance factor is first introduced to guide the design of perovskitoid energetic materials (PEMs). In conjunction with [H2DABCO](ClO4)2·H2O (DAP‐0) and [H2DABCO][M(ClO4)3] (M=Na+, K+, and NH4+ for DAP‐1, ‐2, and ‐4), the physiochemical properties of the two series are investigated between PEMs and non‐perovskites (TDPI‐0 and DAP‐0). The experimental results show that PEMs have great advantages in improving the thermal stability, detonation performance, initiation capability, and regulating sensitivity. The influence of X‐site replacement is illustrated by hard–soft‐acid–base (HSAB) theory. Especially, TDPIs possess much stronger initiation capability than DAPs, which indicates that periodate salts are in favor of deflagration‐to‐detonation transition. Therefore, PEMs provide a simple and feasible method for designing advanced high energy materials with adjustable properties.
In order to study the design and preparation of new coordination primary explosive, the influence of ligand on the performance was explored. Using the low-energy, low-nitrogen pyrrole as the skeleton and the hydrazide group as the target, the ligand 1H-pyrrole-2-carbohydrazide (PRCA) was designed, the two ECCs [Cu(PRCA)2(H2O)(ClO4)]ClO4·C2H5OH (ECCs-1·C 2 H 5 OH) and [Cu(PRCA)2(H2O)(ClO4)]ClO4·2H2O (ECCs-1·2H 2 O) were prepared, and [Cu(PRCA)2(H2O)(ClO4)]ClO4 (ECCs-1) was obtained by a simple drying method. The structure of the target compound was confirmed by single-crystal X-ray diffraction, infrared (IR), and elemental analysis (EA) characterization. Physicochemical performance tests show that ECCs-1 has better thermal stability (T d = 219 °C) and is more sensitive to impact sensitivity (IS = 7 J) and friction sensitivity (FS = 16 N). The detonation performance prediction results show that the detonation velocity and pressure of ECCs-1 are not high (D EXPLO 5 = 6.2 km s–1, P EXPLO 5 = 16.2 GPa). However, detonation performance tests show that ECCs-1 has an extremely strong detonation ability.
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