Assembling Hybrid Energetic Materials with Controllable Interfacial Microstructures by Electrospray

Abstract

Constructing hybrid energetic materials (HEMs) consisting of nanothermites and organic high explosives is an efficient strategy to regulate the reactivity of energetic composites. To investigate the role of interfacial microstructures in determining the reactivity of HEMs, we employ electrospray, one ramification of electrohydrodynamic atomization, to assemble Al/CuO and hexanitrohexaazaisowurtzitane (CL-20) into composites with various morphologies from different solvent systems. The morphology and compositional information of the assembled clay-like or granular HEMs, which are obtained from ketone, ester, or mixtures of alcohol and ether, are confirmed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The phase transition of CL-20 due to the fast evaporation of charged droplets and insufficient time for recrystallization is studied by Fourier transform infrared spectroscopy (FTIR). Thermogravimetric-differential scanning calorimetry (TG-DSC) is applied to investigate the thermodynamic behaviors and synergistic effect of the nanothermite and high explosive. Enhancements in combustion performance and pressurization characteristics of the as-sprayed HEMs have been observed through open burn tests and pressure cell tests. Granular HEMs show high gas generation and high pressurization rate, while nitrocellulose (NC) fibers existing in the clay-like HEMs would weaken the reactivity to a certain extent. HEMs obtained from the mixture of n-propanol and diethyl ether, in which nano-CL-20 exists as independent particles rather than a matrix, exhibit high gas generation but low pressurization rate. The results indicate that the energy releasing performance of the prepared HEMs can be readily regulated by constructing various interfacial microstructures to satisfy the broad requirements of energy sources.

Numerical Simulation of Multifunctional Projectile Penetrating Reinforced Concrete Target Plate Based on Sensor Data Acquisition

“…Kinetic energy is proportional to the quadratic of velocity, so increasing the initial velocity of the projectile is the most important way to enhance its penetration and damage capabilities. In addition, increasing the velocity of the projectile can also improve its surprise defense capability and enhance its combat performance [3]. In recent years, the focus of research on projectile penetration of concrete and other hard targets has shifted from the general drilling projectile (penetration initial velocity below 600 m/s) to the advanced drilling projectile (penetration initial velocity bounded by 1000~1500 m/s) [4].…”

Recent Progress on Synthesis, Characterization, and Performance of Energetic Cocrystals: A Review

“…Bennion and Matzger [ 29 ] discuss the cocrystallization of TNT, HMX, and other materials with energetic and non-energetic coformers, with special emphasis on the intermolecular interactions, sensitivity of resultant ECCs towards external stimuli, and impact of oxygen-rich and oxygen-deficient cocrystallizing molecules on detonation performance. Another review encompasses thermodynamic aspects, molecular stacking, and intermolecular interactions such as halogen and hydrogen bonding, and π interaction between the molecular cocrystals of energetic materials [ 14 , 30 ]. Different methods for the preparation of ECCs, specially based on CL-20 and HMX, their formation mechanisms, and their thermodynamic, detonating, and structural properties are also discussed in another review by Xue et al [ 3 ].…”

Spray Mode and Monodisperse Droplet Properties of an Electrospray

“… 3 , 4 In addition, repulsion between droplets occurs because they are sprayed into the electric field between the nozzle and a substrate, and the droplets are charged with (−) ions on their surface. 5 As a result, polymerization and combination rarely occur between different droplets. 6 Therefore, it is possible to generate uniform and fine droplets compared to other spray systems, and scattering is minimal owing to the characteristics of the charged droplets.…”

“… 7 − 10 Based on these characteristics, electrospraying has been applied in various industrial fields, such as secondary battery electrolytes, surface coating spraying of ships, filter dust collectors to remove particulate matter, and food packaging manufacturing. 11 − 14 …”

“…Since the electrospray system requires the use of electrical signals, it can achieve faster responses and excellent reproducibility compared to other spray systems . In the electrospray system, the droplet size and movement can be easily controlled by changing the external environment, and its structure is simpler than that of other spray systems since it can be configured by adjusting the applied high voltage. , In addition, repulsion between droplets occurs because they are sprayed into the electric field between the nozzle and a substrate, and the droplets are charged with (−) ions on their surface . As a result, polymerization and combination rarely occur between different droplets .…”