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

Rahman, Asad; Chin, Jit Kai; Cheah, Kean How

doi:10.3390/aerospace5010029

Cited by 17 publications

(8 citation statements)

References 34 publications

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“…This method is suitable for the production of ADN particles under high humidity conditions because ADN is not exposed to the atmosphere during the production process. The pellets obtained by this method had a hemispherical morphology, and the size of the pellets was comparable to that of ADN particles obtained by melt granulation method [87].…”

Section: Surface Coating Technologysupporting

confidence: 59%

Anti‐hygroscopicity technologies for ammonium dinitramide: A review**

Tian

Zhao

Chen

et al. 2023

Propellants Explo Pyrotec

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Valuable propellants have the characteristics of high impulse, low pollution, and strong stability, and oxidizers play a substantial role in determining the performance of propellants. Ammonium dinitramide (ADN) is a relatively promising oxidizer due to its high‐energy and chlorine‐free characteristics. However, although ADN exhibits high energy performance compared with traditional oxidizers, the high hygroscopicity of ADN when exposed to high humidity restricts its broader application in solid propellants. This review highlights the necessity of utilizing anti‐hygroscopicity strategies with ADN to extend its application. The anti‐hygroscopicity mechanism of ADN is summarized by calculations and experimental results. Anti‐hygroscopicity technologies that can be used with ADN include prilling, surface coating, and co‐crystallization, and these technologies are comprehensively summarized herein. This review is intended to provide insight into the use of anti‐hygroscopicity technologies with ADN, highlight the challenges of these methods, and point out future development directions.

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Section: Surface Coating Technologysupporting

confidence: 59%

Anti‐hygroscopicity technologies for ammonium dinitramide: A review**

Tian

Zhao

Chen

et al. 2023

Propellants Explo Pyrotec

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“…Additives can act on the surface of the ADN particles to minimize hygroscopicity like graphene flakes , reduce surface tension with surfactants or promote ADN emulsion change with protective colloids . Nanoparticles of silicon dioxide have been used as a protective colloid to promote emulsification caused by steric effects.…”

Section: Resultsmentioning

confidence: 99%

“…The agitator rotation ( N A ) was fixed at 700, 800, 1000 or 1200 rpm and the processes were run for 5 minutes. Also, the effect of the volumetric fraction was evaluated by using different ADN mass values, 0.15, 0.30, 0.45 and 1.00 g. In some of the experiments, 0.5 wt% CAB−O‐SIL® (type M5−200 m 2 g −1 ) was added as a protective colloid in the emulsion . The thermal shock was applied at the end of the process by cutting the hot fluid and simultaneously opening the cold fluid in the circulator while still in agitation, which aimed to keep droplets from deforming or coalescing during cooling.…”

Section: Methodsmentioning

confidence: 99%

ADN Recrystallization and Microencapsulation with HTPB by Simple Coacervation

Silva

Cardoso

Silva

et al. 2020

Propellants Explo Pyrotec

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Ammonium dinitramide (ADN) has been considered the potential substitute for ammonium perchlorate in solid green propellants. However, it has also some drawbacks due to its high hygroscopicity and chemical incompatibility with some of the components present in composite propellant formulations. On the other hand, ADN melts at temperatures below degradation, which makes emulsion crystallization an important method to prepare spherical ADN particles that benefit both propellant slurry processing and casting. Spherical ADN particles were prepared by emulsion crystallization to be used for the microencapsulation studies, and whose method was assessed to better understand which parameters may affect the ADN particles formation. Microencapsulation protects ADN particles as it addresses hygroscopicity besides the given protection from chemical incompatibility. Polyurethane made of hydroxyl-terminated polybutadiene was selected as a coating material because of its common use in propellants as a binder. Also, the good performance of methylene diphenyl diisocyanate as a curing agent was such that it was used in the whole study. The number of layers and the processing time played important roles in the formation of the capsule as seen in the impermeability tests. Besides, drying at 50°C for 168 h showed to be even more beneficial on average for the capsule protective property. Chemical compatibility between the capsule and ADN was confirmed at 60°C which allows it to be used as a protective coating. However, the obtained average coating thickness of ten microns has to be reduced yet with more efficient protective coating materials.

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“…But the lower stability must not exclude its application in some types of rocketry systems. AN and ADN heats of explosion are higher than that of AP.ADN possesses lower critical relative humidity (RH) than AN and to prevent from absorbing moisture during handling, storage and processing, RH in the atmosphere must be kept below this level or to coat its surface with a polymer (hydroxyl terminated polybutadiene, polystyrene, or polyacrylate) [16].…”

Section: Structurementioning

confidence: 99%