Safer Pyrotechnic Obscurants Based on Phosphorus(V) Nitride.

The potential of phosphorus(V) nitride, P3 N5 , as a replacement for red phosphorus, PR , in pyrotechnic obscurants has been theoretically and experimentally investigated. P3 N5 can be safely mixed with KNO3 and even KClO3 and KClO4 . The corresponding formulations are surprisingly insensitive to friction and only mildly impact-sensitive. P3 N5 /KNO3 pyrolants with ξ=20-80 wt % P3 N5 burn 200 times faster than the corresponding mixtures based on PR and generate a dense smoke. Hence obscurants based on P3 N5 /KNO3 have a figure of merit that by far exceeds that of current state-of-the-art PR -based obscurants. Furthermore, unlike PR , which slowly degrades in moist air to phosphoric acids and phosphine (PH3 ), P3 N5 is stable under these conditions and does not produce any acids or PH3 . P3 N5 is hence a safe, stable, and powerful replacement for PR for use in insensitive munitions.

Combustion Synthesis of Functionalized Carbonated Boron Nitride Nanoparticles and Their Potential Application in Boron Neutron Capture Therapy.

In this research, we developed boron-rich nanoparticles that can be used for boron neutron capture therapy as potential carriers for boron delivery to cancerous tissues. Functionalized carbonated boron nitride nanostructures (CBNs) were successfully synthesized in self-propagating combustion waves in mixtures of high-nitrogen explosives and boron compounds. The products' composition, morphology, and structural features were investigated using Fourier transform infrared spectroscopy, powder X-ray diffraction, low-temperature nitrogen sorption analysis, thermogravimetric analysis, high-resolution scanning electron microscopy, and high-resolution transmission electron microscopy. The extreme conditions prevailing in combustion waves favor the formation of nanosized CBN hollow grains with highly disordered structures that are properly functionalized on the surface and inside the particles. Therefore, they are characterized by high porosity and good dispersibility in water, which are necessary for medical applications. During biological tests, a concentration-dependent effect of the obtained boron nitride preparations on the viability of normal and neoplastic cells was demonstrated. Moreover, the assessment of the degree of binding of fluorescently labeled nanoparticles to selected cells confirmed the relationships between the cell types and the concentration of the preparation at different incubation time points.

Synthesis and Characterization of Boron Carbide Nanoparticles as Potential Boron-Rich Therapeutic Carriers.

Boron carbide is one of the hardest materials in the world which can be synthesized by various methods. The most common one is a carbothermic or magnesiothermic reduction of B2O3 performed at high temperatures, where the obtained powder still requires grinding and purification. The goal of this research is to present the possibility of synthesizing B4C nanoparticles from elements via vapor deposition and modifying the morphology of the obtained powders, particularly those synthesized at high temperatures. B4C nanoparticles were synthesized in the process of direct synthesis from boron and carbon powders heated at the temperature of 1650 °C for 2 h under argon and characterized by using scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X-ray diffraction analysis, and dynamic light scattering measurements. The physicochemical characteristics of B4C nanoparticles were determined, including the diffusion coefficients, hydrodynamic diameter, electrophoretic mobilities, and zeta potentials. An evaluation of the obtained B4C nanoparticles was performed on several human and mouse cell lines, showing the relation between the cytotoxicity effect and the size of the synthesized nanoparticles. Assessing the suitability of the synthesized B4C for further modifications in terms of its applicability in boron neutron capture therapy was the overarching goal of this research.

Detonation properties of 1,1-diamino-2,2-dinitroethene (DADNE).

1,1-Diamino-2,2-dinitroethene (DADNE, FOX-7) is an explosive of current interest. In our work, an advanced study of detonation characteristics of this explosive was performed. DADNE was prepared and recrystallized on a laboratory scale. Some sensitivity and detonation properties of DADNE were determined. The detonation performance was established by measurements of the detonation wave velocity, detonation pressure and calorimetric heat of explosion as well as the accelerating ability. The JWL (Jones-Wilkins-Lee) isentrope and the constant-gamma isentrope for the detonation products of DADNE were also found.

Carbon encapsulated magnetic nanoparticles for biomedical applications: thermal stability studies.

Carbon encapsulated magnetic nanoparticles may find many prospective biomedical applications, e.g., in drug and gene delivery systems, disease detection, cancer therapy, rapid toxic cleaning, biochemical sensing, and magnetic resonance imaging. Each of these applications hinges on the relationship between magnetic fields and biological systems. Herein we present the results on the thermal stability of carbon encapsulated magnetic nanoparticles. The products were synthesized by using induction radio frequency (RF) thermal plasma. Phase composition and morphology were studied by powder X-ray diffraction and HRTEM, respectively. Thermal stability was investigated by thermogravimetry and differential thermal analyses. Carbon nanostructures were thermally stable up to 500 K.

Combustion synthesis as a novel method for production of 1-D SiC nanostructures.

1-D nanostructures of cubic phase silicon carbide (beta-SiC) were efficiently produced by combustion synthesis of mixtures containing Si-containing compounds and halocarbons in a calorimetric bomb. The influence of the operating parameters on 1-D SiC formation yield was studied. The heat release, the heating rate, and the chamber pressure increase were monitored during the process. The composition and structural features of the products were characterized by elemental analysis, X-ray diffraction, differential thermal analysis/ thermogravimetric technique, Raman spectroscopy, scanning and transmission electron microscopy, and energy-dispersive X-ray spectrometry. This self-induced growth process can produce SiC nanofibers and nanotubes ca. 20-100 nm in diameter with the aspect ratio higher than 1000. Bulk scale Raman studies showed the product to be comprised of mostly cubic polytype of SiC and that finite size effects are present. We believe that the nucleation mechanism involving radical gaseous species is responsible for 1-D nanostructures growth. The present study has enlarged the family of nanofibers and nanotubes available and offers a possible, new general route to 1-D crystalline materials.

Synthesis and explosive properties of copper(II) chlorate(VII) coordination polymer with 4-amino-1,2,4-triazole bridging ligand.

Copper(II) chlorate(VII) coordination polymer with 4-amino-1,2,4-triazole as bridging ligand was prepared and characterized by elemental analysis, IR spectra and TG/DTA analyses. Sensitivity and detonator tests were also preformed. The compound has a 1D chain structure in which Cu(II) ions are linked by triple triazole N1,N2 bridges. It is a detonat with performance close to that of lead azide, but at the same time it shows moderate sensitivity to thermal (explosively decomposes above 250 degrees C) and mechanical stimuli (sensitivity to friction 10N).

High performance liquid chromatography of 1,1-diamino-2,2-dinitroethene and some intermediate products of its synthesis.

1,1-Diamino-2,2-dinitroethene (DADNE, FOX-7) is a novel explosive with low sensitivity and high performance. The unique combination of the valuable properties is a result of the structure of the compound. The molecular packing of DADNE consists of layers with strong intermolecular hydrogen bonds which stabilize the molecule. In the paper, the results of research the purity of DADNE in different recrystallization conditions and some intermediate products of its synthesis were presented. High performance liquid chromatography (HPLC) method based on the porous graphitic carbon (PGC) column packing material has been developed. Two variants of mobile phases in different pH values: acetonitrile-water and methanol-water with ammonia (NH(3)) and with trifluoroacetic acid (TFA) were used. The probable mechanism of interaction between the analyte, the stationary phase, and the mobile phase was suggested.