Preparation and characterization of nano NC/HMX composite particles

Abstract

Nano nitrocellulose/cyclotetramethylene tetranitramine (NC/HMX) composite particles were precipitated from their co-solutions by the spray drying method. The nano composite samples were characterized by scanning electron microscope, transmission electron microscope and X-ray diffraction. Impact sensitivity and thermal decomposition properties of nano composites were also measured and analyzed. Results show that the product particles are close to spherical in shape and range from 0.5 μm to 5 μm in size. In the product particles, β-HMX particles with size ranging from 50 nm to 100 nm are uniformly and discretely dispersed in NC binders. The drop height of nano NC/HMX composite particles (66.1 cm) is more than triple as high as that of raw HMX (21.6 cm), exhibiting considerably low impact sensitivity. Moreover, nano composite particles are easier to decompose and decomposed more rapidly than do raw HMX under the thermal stimulus due to the lower peak temperature and activation energy and higher reaction rate. Therefore, nano composites are expected to be candidates filled in high burning rate propellants.

Characterization of Electrospinning Prepared Nitrocellulose (NC)-Ammonium Dinitramide (ADN)-Based Composite Fibers

“…In many methods of nanosized energetic materials preparation, electrospinning is a selective preference due to its versatile choice of raw materials, the relatively economic hardware, the superior design flexibility of the composition, and the feasibility of mass production [ 21 , 22 ]. In recent years, many micro/nanosized NC-based composites have been designed and produced by electrospinning in order to improve the combustion performance [ 23 , 24 ], to reduce the aggregation degree of the nanoparticles [ 25 , 26 ], or to decrease the sensitivity of high energetic explosives, such as hexahydro-1,3,5-trinitro- 1,3,5-triazine (RDX) [ 27 , 28 ]; octahydro-1,3,5,7-tetranitro-1,3,5,7- tetrazocine (HMX) [ 29 , 30 ]; or 2,4,6,8,10,12- hexanitro-2,4,6,8,10,12- hexanitrohexaazaiso-wurzitane (CL-20) [ 31 ]. However, those electrospun composites reported above were composed of nitrocellulose and high explosives which had a negative oxygen balance (OB), such as RDX (OB = −21.6%), HMX (OB = −21.6%), CL-20 (OB = −10.9%), et al It was reported that compounds with an OB close to zero demonstrate increased energy release [ 32 ]; hence, it is expected that the energy release rate can be improved by adding oxidizer into those electrospun composites.…”

A Hot Spots Ignition Probability Model for Low-Velocity Impacted Explosive Particles Based on the Particle Size and Distribution

“…Wu and Huang [6] have used high-speed photography to record the impact response behavior of the monolayer HMX particles under drop weight and analyzed its ignition mechanism. An et al [7] found that the mechanical sensitivity of HMX reduces obviously if it covered with HTPB. The thermal impact sensitivities of PETN, TATP, HMX, and silver azide (AgN 3 ) as a function of temperature are obtained [8].…”