Tuning the Energetic Performance of CL-20 by Surface Modification Using Tannic Acid and Energetic Coordination Polymers.

The energetic performance of hexanitrohexaazaisowurtzitane (CL-20) was modulated with two energetic coordination polymers (ECPs), [Cu(ANQ)2(NO3)2] and [Ni(CHZ)3](ClO4)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(NO3)2] and [Ni(CHZ)3](ClO4)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(NO3)2] is 58% less than that of CL-20 with no energy decrease. On the other hand, CL-20/TA/[Ni(CHZ)3](ClO4)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.

Theoretical studies on the thermodynamic properties, densities, detonation properties, and pyrolysis mechanisms of trinitromethyl-substituted aminotetrazole compounds.

Trinitromethyl-substituted aminotetrazoles with -NH2, -NO2, -N3, and -NHC(NO2)3 groups were investigated at the B3LYP/6-31G(d) level of density functional theory. Their sublimation enthalpies, thermodynamic properties, and heats of formation were calculated. The thermodynamic properties of these compounds increase with temperature as well as with the number of nitro groups attached to the tetrazole ring. In addition, the detonation velocities and detonation pressures of these compounds were successfully predicted using the Kamlet-Jacobs equations. It was found that these compounds exhibit good detonation properties, and that compound G (D = 9.2 km/s, P = 38.8 GPa) has the most powerful detonation properties, which are similar to those of the well-known explosive HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocine). Finally, the electronic structures and bond dissociation energies of these compounds were calculated. The BDEs of their C-NO2 bonds were found to range from 101.9 to 125.8 kJ/mol(-1). All of these results should provide useful fundamental information for the design of novel HEDMs.

Theoretical investigation of a novel high density cage compound 4,8,11,14,15-pentanitro-2,6,9,13-tetraoxa-4,8,11,14,15-pentaazaheptacyclo[5.5.1.1(3,11).1(5,9)] pentadecane.

A novel polynitro cage compound 4,8,11,14,15-pentanitro-2,6,9,13-tetraoxa-4,8,11,14,15-pentaazaheptacyclo [5.5.1.1(3,11).1(5,9)]pentadecane(PNTOPAHP) has been designed and investigated at the DFT-B3LYP/6-31(d) level. Properties, such as electronic structure, IR spectrum, heat of formation, thermodynamic properties and crystal structure have been predicted. This compound is most likely to crystallize in C2/c space group, and the corresponding cell parameters are Z = 8, a = 29.78 Å, b = 6.42 Å, c = 32.69 Å, α = 90.00°, ß = 151.05°, γ = 90.00° and ρ = 1.94 g/cm(3). In addition, the detonation velocity and pressure have also been calculated by the empirical Kamlet-Jacobs equation. As a result, the detonation velocity and pressure of this compound are 9.82 km/s, 44.67 GPa, respectively, a little higher than those of 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazaisowurtzitane(TEX, 9.28 km/s, 40.72 GPa). This compound has a comparable chemical stability to TEX, based on the N-NO(2) trigger bond length analysis. The bond dissociation energy ranges from 153.09 kJ mol(-1) to 186.04 kJ mol(-1), which indicates that this compound meets the thermal stability requirement as an exploitable HEDM.

[Research on SCB discharge behavior with atomic emission spectroscopy].

Semiconductor bridge (SCB) was utilized to ignite energetic materials with thin film discharge and characterized of low input energy, high safety and logic control possibility. SCB discharge was diagnosticated with atomic emission spectroscopy. Firstly, discharge temperature was acquired with copper atom spectral lines 510.5 and 521.8 nm, and electron density was calculated with silicon atom spectral line 390.5 nm and corresponding ion line 413.0 nm. As for resistance 1.0 omega of SCB with the discharge voltage of 20 V and capacity of 47 microF, its discharge temperature was about 2 500-4 300 K and electron density 10(16) cm(-3). Meanwhile, the temperature and density V(s) time distributions were acquired simultaneously. And then with the diagnosis results, the discharge behaviors of two sorts of SCB were judged according to plasma space-dimension and time-dimension restrictions. This research set up an efficient technique for the diagnosis of transient small-size discharge behavior and provided instructions for the design of SCB and discharge condition.

[Emission spectroscopy diagnostics of plasma electron temperature].

Electron temperature is one of the important parameters of plasma. It is very difficult to measure the electron temperature exactly and instantly owing to its complexity during discharge. As a plasma diagnostics technique, emission spectroscopy is widely applied in the study and diagnosis of any kind of plasma, because of its simple instrument system, noninterference of measurement, high sensitivity and fast responsibility. In the present paper, some methods for plasma electron temperature diagnosis, such as two lines method, multiline slope method, isoelectronic line method, Saha-Boltzmann equation, absolute intensity method, were introduced. And the applications of these methods were reviewed to provide reference for choosing appropriate methods in practice.