Prilling and coating of Ammonium Dinitramide (ADN) solid green propellant in toluene mixture using ultrasound sonication

Asad Rahman, Jitkai Chin, Kean How Cheah

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Ammonium Dinitramide (ADN) in its generic form has a long needle shaped structure, which hinders higher solid loading. Therefore, it is of utmost importance to optimize its crystal morphology into octagonal shapes. Moreover, the low critical humidity level of ADN renders it unusable in a humid climate. Hence, encapsulation with a hydrophobic polymer is necessary. In the present work, ADN was synthesized by nitration of potassium sulfamate with mixed acid nitration. The product was then mixed with toluene, graphene, citryl ammonium butyl, Cab-o-sil, and coating polymer (Polystyrene or HTPB) and treated with ultrasound to obtain semi-spherical ADN-coated particles. The method offers a reduction in operating temperature and elimination of ADN melting in the shape-altering process. In addition, the ADN product has a similar particle size and thermal stability compared to those in a conventional ADN melt-prilling method. The ADN product investigated under SEM confirms the particle morphological change from long needles into semi-spherical shapes. The particle size obtained, in the micrometer range, is ideal for higher theoretical maximum density. Furthermore, the ultrasound-treated ADN particles show significant reduction in moisture absorption, from 68% to 16% at 65% relative humidity. The DSC result shows no degradation of thermal stability of the coated particles.

Original languageEnglish
Article number29
JournalAerospace
Volume5
Issue number1
DOIs
Publication statusPublished - 9 Mar 2018
Externally publishedYes

Fingerprint

Nitration
Sonication
Propellants
Needles
Toluene
Atmospheric humidity
Thermodynamic stability
Ultrasonics
Particle size
Coatings
Polymers
Encapsulation
Graphene
Potassium
Polystyrenes
Melting
Moisture
Degradation
Crystals
Scanning electron microscopy

Cite this

@article{ccb007e9048b4278ad05e8b641f09be8,
title = "Prilling and coating of Ammonium Dinitramide (ADN) solid green propellant in toluene mixture using ultrasound sonication",
abstract = "Ammonium Dinitramide (ADN) in its generic form has a long needle shaped structure, which hinders higher solid loading. Therefore, it is of utmost importance to optimize its crystal morphology into octagonal shapes. Moreover, the low critical humidity level of ADN renders it unusable in a humid climate. Hence, encapsulation with a hydrophobic polymer is necessary. In the present work, ADN was synthesized by nitration of potassium sulfamate with mixed acid nitration. The product was then mixed with toluene, graphene, citryl ammonium butyl, Cab-o-sil, and coating polymer (Polystyrene or HTPB) and treated with ultrasound to obtain semi-spherical ADN-coated particles. The method offers a reduction in operating temperature and elimination of ADN melting in the shape-altering process. In addition, the ADN product has a similar particle size and thermal stability compared to those in a conventional ADN melt-prilling method. The ADN product investigated under SEM confirms the particle morphological change from long needles into semi-spherical shapes. The particle size obtained, in the micrometer range, is ideal for higher theoretical maximum density. Furthermore, the ultrasound-treated ADN particles show significant reduction in moisture absorption, from 68{\%} to 16{\%} at 65{\%} relative humidity. The DSC result shows no degradation of thermal stability of the coated particles.",
keywords = "Ammonium Dinitramide (ADN), Green propellant, Polymer coating, Ultrasound sonication",
author = "Asad Rahman and Jitkai Chin and Cheah, {Kean How}",
year = "2018",
month = "3",
day = "9",
doi = "10.3390/AEROSPACE5010029",
language = "English",
volume = "5",
journal = "Aerospace",
issn = "2226-4310",
publisher = "Multidisciplinary Digital Publishing Institute (MDPI)",
number = "1",

}

Prilling and coating of Ammonium Dinitramide (ADN) solid green propellant in toluene mixture using ultrasound sonication. / Rahman, Asad; Chin, Jitkai; Cheah, Kean How.

In: Aerospace, Vol. 5, No. 1, 29, 09.03.2018.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Prilling and coating of Ammonium Dinitramide (ADN) solid green propellant in toluene mixture using ultrasound sonication

AU - Rahman, Asad

AU - Chin, Jitkai

AU - Cheah, Kean How

PY - 2018/3/9

Y1 - 2018/3/9

N2 - Ammonium Dinitramide (ADN) in its generic form has a long needle shaped structure, which hinders higher solid loading. Therefore, it is of utmost importance to optimize its crystal morphology into octagonal shapes. Moreover, the low critical humidity level of ADN renders it unusable in a humid climate. Hence, encapsulation with a hydrophobic polymer is necessary. In the present work, ADN was synthesized by nitration of potassium sulfamate with mixed acid nitration. The product was then mixed with toluene, graphene, citryl ammonium butyl, Cab-o-sil, and coating polymer (Polystyrene or HTPB) and treated with ultrasound to obtain semi-spherical ADN-coated particles. The method offers a reduction in operating temperature and elimination of ADN melting in the shape-altering process. In addition, the ADN product has a similar particle size and thermal stability compared to those in a conventional ADN melt-prilling method. The ADN product investigated under SEM confirms the particle morphological change from long needles into semi-spherical shapes. The particle size obtained, in the micrometer range, is ideal for higher theoretical maximum density. Furthermore, the ultrasound-treated ADN particles show significant reduction in moisture absorption, from 68% to 16% at 65% relative humidity. The DSC result shows no degradation of thermal stability of the coated particles.

AB - Ammonium Dinitramide (ADN) in its generic form has a long needle shaped structure, which hinders higher solid loading. Therefore, it is of utmost importance to optimize its crystal morphology into octagonal shapes. Moreover, the low critical humidity level of ADN renders it unusable in a humid climate. Hence, encapsulation with a hydrophobic polymer is necessary. In the present work, ADN was synthesized by nitration of potassium sulfamate with mixed acid nitration. The product was then mixed with toluene, graphene, citryl ammonium butyl, Cab-o-sil, and coating polymer (Polystyrene or HTPB) and treated with ultrasound to obtain semi-spherical ADN-coated particles. The method offers a reduction in operating temperature and elimination of ADN melting in the shape-altering process. In addition, the ADN product has a similar particle size and thermal stability compared to those in a conventional ADN melt-prilling method. The ADN product investigated under SEM confirms the particle morphological change from long needles into semi-spherical shapes. The particle size obtained, in the micrometer range, is ideal for higher theoretical maximum density. Furthermore, the ultrasound-treated ADN particles show significant reduction in moisture absorption, from 68% to 16% at 65% relative humidity. The DSC result shows no degradation of thermal stability of the coated particles.

KW - Ammonium Dinitramide (ADN)

KW - Green propellant

KW - Polymer coating

KW - Ultrasound sonication

UR - http://www.scopus.com/inward/record.url?scp=85058207645&partnerID=8YFLogxK

U2 - 10.3390/AEROSPACE5010029

DO - 10.3390/AEROSPACE5010029

M3 - Article

VL - 5

JO - Aerospace

JF - Aerospace

SN - 2226-4310

IS - 1

M1 - 29

ER -