Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Theoretical study on the detonation properties of energetic TNAD molecular derivatives

Following the successful synthesis of the TNAD (1,4,5,8-tetranitro-1,4,5,8-tetraazadecalin), the amine reactant is theoretically replaced to yield the hypothesized TNAD molecular derivatives. Density functional theory (DFT) calculation method was applied to model TNAD and its derivatives. In this investigation, the target molecular volumes were initially obtained using the group additivity approach, and then transferred into molecular densities. The densities and the least square estimated enthalpies of formation (ΔH_f) of TNAD, and the corresponding derivatives, were obtained and the Kamlet–Jacobs empirical equations were used to determine the related detonation velocity and detonation pressure. The simulation results reveal that three of the TNAD molecular derivatives perform similarly to the traditionally used TNT (2,4,6-trinitrotoluene). Four other derivatives outperform TNT, with performance that approach that of RDX (1,3,5-trinitro-1,3,5-triazacyclohexane).     

Surface modification of detonation nanodiamonds by the perfluorobutyl radical

The method was developed for surface defunctionalization of detonation nanodiamonds by substitution of a perfluorinated organic radical for hydroxyl and carboxyl groups. Size-mass distributions of modified particles of detonation nanodiamonds in water and toluene were studied     

Branched-chain nature of hydrogen combustion in the detonation mode

Minor admixtures of the simplest hydrocarbons can prevent detonation and break down a steady-state detonation wave in hydrogen-air mixtures at atmospheric and higher pressures. Therefore, the determining role in the appearance and propagation of the detonation wave is played by the branched mechanism and, accordingly, by the competing chain branching and termination reactions. Without taking into account these reactions, combustion theory cannot explain the basic regularities of the process, including the concentration limits of detonation.     

Theoretical investigations on the density,detonation performance and stability of fluorinated hexanitroadamantanes

Structural Chemistry - Cage compounds such as hexanitroadamantane (HNA) and hexanitrohexaazaisowurtzitane (HNIW, CL-20) constitute an important category of energetic compounds owing to the strained...     

Surface characterization of detonation nanodiamond particles

Specific features of formation of stable suspensions of detonation nanodiamond (DND) in media of different polarities were considered. A relation between the dispersity of DND particles and their surface activity was found. The surface activity of diamond nanoparticles (10–100 nm) is significantly (by a factor of 4) lower than that of submicron-sized particles, which indicates satisfactory environmental parameters of nanosized diamonds. An attempt to reduce the surface energy by grafting hydrophobic radicals led to appreciable increase in the dispersity of DND particles, thereby reducing the risk of harmful DND effect on the environment.     

Immobilization of enzyme on detonation nanodiamond for highly efficient proteolysis

Immobilization of enzyme on detonation nanodiamond (dND, 3-10 nm) and its application for efficient proteolysis have been demonstrated. By evaluation of the Michaelis constant (K_m) and maximum velocity (V_max) of immobilized enzyme, its activity was not impaired significantly by immobilization. And enzyme immobilized on dNDs exhibited much better thermal and chemical stabilities than its free counterpart and maintained high activity even after 10 times reuse. The efficient proteolysis by trypsin immobilized on dNDs (dND-trypsin) is demonstrated with the digestion of myoglobin (or other model protein) in a short time (5 min). Large numbers of identified peptides obtained by dNDs-trypsin enable a higher degree of sequence coverage and more positive identification of proteins than those obtained by in-solution digestion and the commercial immobilized trypsin beads, respectively. Moreover, immobilization of peptide-N-glycosidase F (PNGase F) on dNDs was realized and resulted in faster sequential glycosidase digestion of glycopeptides in less than 10 min.     

Theoretical investigation on the structures,densities, and detonation properties of polynitrotetraazaoctahydroanthracenes

The polynitrotetraazaoctahydroanthracenes were optimized to obtain their molecular geometries and electronic structures at density functional theory–B3LYP/6‐31+G(d) level. Detonation velocities (D) and detonation pressures (P) were estimated for this nitramine compounds using Kamlet‐Jacobs equations, based on the theoretical densities (ρ) and heats of formation. It is found that there are good linear relationships between volume, density, detonation velocity, detonation pressure and the number of nitro group. Thermal stability of the compounds was investigated by calculating the bond dissociation energies and energy gap (ΔE_LUMO–HOMO). The simulation results reveal that molecule H performs similarly to famous explosive RDX. These results provide basic information for molecular design of novel high energetic density compounds. © 2011 Wiley Periodicals, Inc.     

Natural limit of the number of copper ions chemisorbed on the surface of a detonation nanodiamond

The upper limit of the amount of copper ions that can be grafted to the detonation nanodiamond surface has been calculated. A maximum of 34 wt% copper can be grafted to carboxylated and hydroxylated 5 nm nanodiamonds. The results of calculations have been compared with the experimental and published data.     

VLW equation of state of detonation products

Based on the virial theory, we proposed VLW equation of state of detonation products (VLW EOS). Its basic theory and applications were described. The distinct features of the VLW EOS were First, the detonation performance of the new high energy density materials could be predicted more reliably. Second, it had extensive application. The detonation parameters of both the condensed high energy density materials and the gaseous fuel air explosives could be calculated. Moreover, combustion performance of propellants could also be precisely calculated. The calculation results were satisfactory. Supported by the National Natural Science Foundation of China (Grant No. 1860382), and the Science Foundation of China Academy of Engineering Physics (Grant Nos. 920513, 9401009 & 960577)     

Ion-exchange properties of microdispersed sintered detonation nanodiamond

The adsorption of transition metal cations and inorganic anions from aqueous solutions on microdispersed sintered detonation nanodiamond (MSDN) is systematically studied. The selectivity series Fe³⁺ > Al³⁺ > Cu²⁺ > Mn²⁺ > Zn²⁺ > Cd²⁺ > Co²⁺ > Ni²⁺ with maximum adsorption capacity between 2 and 5 µmol g^?1 is obtained. It is found that anions may significantly contribute to the adsorption of transition metal cations, so the adsorption of CH₃COO^?, Cl^?, B₄O₇ ^2?, ClO₄ ^?, I^?, SO₄ ^2?, C₂O₄ ^2?, PO₄ ^3? is also studied. For the first time, dominating adsorption of anions over cations is demonstrated for detonation nanodiamond. The maximum anion-exchange capacity of 50–150 µmol g^?1 is found for MSDN. Beside of electrostatic interactions, the formation of complexes with hydroxyl groups and interaction with metal impurities contribute to the adsorption of B₄O₇ ^2? and PO₄ ^3?, respectively. Therefore, anion exchange selectivity of MSDN is different from that observed for common anion exchange resins. In all cases, the adsorption on MSDN obeys Langmuir law. The pH effect on the adsorption of SO₄ ^2?, PO₄ ^3? and B₄O₇ ^2? is different from that observed for other anions due to specific interactions.     

Polymeric nanocomposites based on fluoropolymers and nanocarbon from detonation synthesis

The effect of modifying additions of nanocarbon from detonation synthesis on the physicomechanical properties of fluorinated copolymers derived from vinylidene fluoride was examined.     

Treatment of detonation carbon in supercritical water

Experimental data on the treatment of detonation carbon in supercritical water are given.