Effects of Select Metal Oxides on the Onset, Rate and Extent of Low Temperature Ammonium Perchlorate Decomposition

Tolmachoff, Erik D.; Baldwin, Lawrence C.; Essel, Jonathan T.; Hedman, Trevor D.; Kalman, Steven E.; Kalman, Joseph

doi:10.1080/07370652.2021.1895914

Cited by 8 publications

(6 citation statements)

References 36 publications

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“…In fact, previous work has identified that the rate of low temperature decomposition is correlated with the thermodynamics of the system. A strong inverse correlation between decomposition rate in the low temperature regime and MO lattice energy was observed [6]. Lattice energy is a thermodynamic quantity.…”

Section: Short Communicationmentioning

confidence: 92%

Are All Solid Propellant Burning Rate Modifiers Catalysts?

Kalman

2022

Propellants Explo Pyrotec

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Solid rocket motors are used for both national defense and launch vehicles. The internal ballistics of the motor depend on the propellant burning rate, which is often modified by burning rate enhancers. Despite the common use, there is not a complete mechanistic understanding of how these modifiers influence the combustion process. In this comment, it is argued that these additives can influence propellant combustion as a catalyst, via thermodynamic means, or a combination. An approach is suggested on how to classify traditional and novel burning rate modifiers as a first step to improving the scientific community's knowledge on the matter.

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Section: Short Communicationmentioning

confidence: 92%

Are All Solid Propellant Burning Rate Modifiers Catalysts?

Kalman

2022

Propellants Explo Pyrotec

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“…It has been well-established [30] that AP decomposes in two steps, named low-temperature decomposition stage and high-temperature decomposition stage. The mass loss was approximately 30 % in the low-temperature decomposition stage of AP [31].…”

Section: Slow Cook-off Behavior Of Apmentioning

confidence: 99%

Effect of Block Structure of Copolyether Binder on Slow Cook‐Off Response of Composite Propellant

Zhang

Ding

et al. 2022

Propellants Explo Pyrotec

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As the typical insensitive propellants, hydroxyl‐terminal block copolyether (HTPE) and hydroxyl‐terminal block copolyether (PET) propellant all belong to copolyether propellants. The two binders of propellants have different arrangements of copolyether structure. But, the effect of copolyether structure arrangement on the slow cook‐off behavior of propellants and its possible mechanism has been unknown. So, in this paper, the slow cook‐off behaviors of HTPE and PET propellants were tested. The result showed PET propellant responded more violently than HTPE propellant. Then, the changes of mass loss, explosion heat, and combustion performance of propellants during the cook‐off test were studied. Combined with the slow cook‐off behavior of AP and binders, the mechanism of block structure effect on slow cook‐off response of propellant was proposed. It expressed that, the binders of HTPE and PET propellant all degraded into liquid products due to the copolyether structure; but the block structure has a significant effect on the chain scission process of copolyether binder, which makes slight degradation and the mild response to slow cook‐off for HTPE propellant. While the binder of PET propellant with the random structure degraded seriously, making more mass loss, bigger explosion heat, and worse combustion performance, the PET propellant responds violently to slow cook‐off.

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“…AP decomposition is typically studied from a solid-state chemistry perspective in which the reaction is initiated at defects in the solid lattice that serve as nucleation sites for decomposition. ,− AP crystals undergo a phase transition from orthorhombic to cubic at 240 °C, and the decomposition behavior of both polymorphs has been studied extensively in previous work. − However, the exact mechanism remains unclear due to the complexity of solid-state chemical reactions and the factors that affect such processes, including (1) particle size, (2) particle morphology, (3) reaction temperature (isothermal reactions), (4) heating rates (nonisothermal reactions), (5) pressure, (6) adsorption/desorption of product gases, and (7) the presence of chemical impurities or additives. , Thermal decomposition of AP is complex; for instance, pure AP typically shows two decomposition events during nonisothermal heating: (1) low-temperature decomposition (LTD) below 300 °C and (2) high-temperature decomposition (HTD) above 300 °C. After undergoing LTD, the resulting AP particles show morphological changes with the formation of porosity on the particle surface, which significantly increases the particle surface area, but without introducing chemical differences from pristine AP. ,− Decomposition typically ceases after LTD until the AP particles are heated to higher temperatures (>300 °C), and this inactivity between events has previously been attributed to the exhaustion of defects (nucleation sites) during LTD. , Consistent with this hypothesis, fine AP particles (<10 μm) typically do not show an LTD event because smaller crystals typically have lower defect levels and, thus, fewer nucleation sites than larger crystals …”

Section: Introductionmentioning

confidence: 99%

“…7,11−13 Decomposition typically ceases after LTD until the AP particles are heated to higher temperatures (>300 °C), and this inactivity between events has previously been attributed to the exhaustion of defects (nucleation sites) during LTD. 9,14 Consistent with this hypothesis, fine AP particles (<10 μm) typically do not show an LTD event because smaller crystals typically have lower defect levels and, thus, fewer nucleation sites than larger crystals. 8 An alternate hypothesis for LTD cessation proposes that the adsorption of product gases (e.g., ammonia) onto the solid surface inhibits the decomposition reaction. 11,15,16 This hypothesis is supported by the differences in AP reactivity when studied in sealed containers where product gases cannot escape compared to open containers in which product gases can easily be removed.…”

Section: ■ Introductionmentioning

confidence: 99%

Enhanced Decomposition of Ammonium Perchlorate–Ethyl Cellulose–Molybdenum Disulfide Nanocomposites

Baca

Garrison

Kuo

et al. 2023

ACS Appl. Mater. Interfaces

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Ammonium perchlorate (AP) is commonly used in propulsion technology. Recent studies have demonstrated that two-dimensional (2D) nanomaterials such as graphene (Gr) and hexagonal boron nitride (hBN) dispersed with nitrocellulose (NC) can conformally coat the surface of AP particles and enhance the reactivity of AP. In this work, the effectiveness of ethyl cellulose (EC) as an alternative to NC was studied. Using a similar encapsulation procedure as in recent work, Gr and hBN dispersed with EC were used to synthesize the composite materials Gr–EC–AP and hBN–EC–AP. Additionally, EC was used because the polymer can be used to disperse other 2D nanomaterials, specifically molybdenum disulfide (MoS2), which has semiconducting properties. While Gr and hBN dispersed in EC had a minimal effect on the reactivity of AP, MoS2 dispersed in EC significantly enhanced the decomposition behavior of AP compared to the control and other 2D nanomaterials, as evidenced by a pronounced low-temperature decomposition event (LTD) centered at 300 °C and then complete high-temperature decomposition (HTD) below 400 °C. Moreover, thermogravimetric analysis (TGA) showed a 5% mass loss temperature (T d5%) of 291 °C for the MoS2-coated AP, which was 17 °C lower than the AP control. The kinetic parameters for the three encapsulated AP samples were calculated using the Kissinger equation and confirmed a lower activation energy pathway for the MoS2 (86 kJ/mol) composite compared to pure AP (137 kJ/mol). This unique behavior of MoS2 is likely due to enhanced oxidation–reduction of AP during the initial stages of the reaction via a transition metal-catalyzed pathway. Density functional theory (DFT) calculations showed that the interactions between AP and MoS2 were stronger than AP on the Gr or hBN surfaces. Overall, this study complements previous work on NC-wrapped AP composites and demonstrates the unique roles of the disperagent and 2D nanomaterial in tuning the thermal decomposition of AP.

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Effects of Select Metal Oxides on the Onset, Rate and Extent of Low Temperature Ammonium Perchlorate Decomposition

Cited by 8 publications

References 36 publications

Are All Solid Propellant Burning Rate Modifiers Catalysts?

Are All Solid Propellant Burning Rate Modifiers Catalysts?

Effect of Block Structure of Copolyether Binder on Slow Cook‐Off Response of Composite Propellant

Enhanced Decomposition of Ammonium Perchlorate–Ethyl Cellulose–Molybdenum Disulfide Nanocomposites

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