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

Abstract

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.

Cellulose Nanofibril/Talc Composite Films with Excellent Barrier Properties by Alternate Hierarchical Method

“…Currently, various nanofillers are valuable for the preparation of packaging materials, for example, two-dimensional (2D) sheets, such as MXene, graphene, and MoS 2 , − are widely used due to their layered structures with large specific surface area. Among the nanosheets, clay showed the advantages of widely available source, cheap cost, and easy processing. − As one kind of clay, talc is a hydrated magnesium silicate mineral with a lamellar structure and has been extensively employed as a filler in papermaking industries .…”

Cu/Carbon Aerogels Derived from HKUST-1 for the Thermal Decomposition of Ammonium Perchlorate

“…However, the high decomposition temperature of AP often led to insufficient decomposition during combustion, which is an important factor that restricted the high-energy development of solid propellants. Therefore, in order to meet practical needs and improve the thermal decomposition process of AP, it was necessary to develop new and efficient thermal catalysts. , …”