Preparation and characterization of nano NC/HMX composite particles

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.