Ammonium Dinitramide (ADN)–Prilling, Coating, and Characterization

Abstract

Ammonium dinitramide (ADN) is the promising oxidizer, which is expected to be applied, e.g., in solid rocket propellants. The manufacturing of spherical ADN particles (the so‐called ADN‐Prills) with useful morphology and reproducible quality is realized by means of the emulsion crystallization process.

Prilling and Coating of Ammonium Dinitramide (ADN) Solid Green Propellant in Toluene Mixture Using Ultrasound Sonication

“…Pristine ADN synthesized in this experiment has long needle-like shape, as shown in Figure 3, compared to pristine ADN prepared by Heintz et al [6]. Spherical ADN particles produced via ultrasound sonication followed by coating with 5% PS and HTPB are shown in Figure 4.…”

“…The filtrate product of prilled ADN particles were then added to a mixture of polystyrene (PS) in 50 mL dichloromethane and evaporated in a rotary evaporator to obtain coated AND [6]. In the second experiment, PS was replaced with hydroxyl-terminated polybutadiene (HTPB).…”

“…Previous experiments have shown that the moisture absorption of ADN is higher than that of AP [4]. The hygroscopicity of ADN can be decreased by coating it with hydrophobic polymers [3,5,6] such as hydroxyl terminated polybutadiene (HTPB), polystyrene (PS), and polyacrylate (PA). Otherwise, specifications given on the particle size, particle layout geometry, and surface area under the experimental conditions have seldom been described in the literature.…”

“…Many methods have been utilized to alter the crystal particle morphology of energetic materials, such as melt prilling [6], ultrasound-assisted crystallization [7], solvent crystallization [8], and spray crystallization [9]. Melt prilling, which is an important process in conventional production of ADN, possesses several drawbacks, such as volumetric expansion in the melting phase and it being hazardous due to high operating temperature.…”

Binder Materials for Green Propellants

“…For many years, the work was focused on preparing suitable crystals or particles [9][10][11][12][13][14][15][16][17][18][19][20][21]. Since 2006, spherical particles of good quality have been produced by the Swedish Defence Research Agency (FOI), Sweden [22], and these were commercialised during 2011 by EURENCO Bofors, Sweden.…”