Decomposition Of AP Research Articles

Synthesis, anti-migration properties and burning rate catalytic properties of ferrocene-based compounds

Five ferrocene (Fc)-based compounds (HQ-Fcs) were synthesized by the condensation reaction of ferrocenecarbonyl chloride with corresponding hydroquinone derivatives. Nuclear magnetic resonance (1H NMR), and Fourier transform infrared (FT-IR) were used as evidence for the synthesis of HQ-Fcs. The electrochemical properties of HQ-Fcs were investigated by cyclic voltammetry (CV) and suggested that these compounds exhibited redox behavior due to ferrocene groups. The burning rate catalytic effect of HQ-Fcs was examined by Thermogravimetric (TG) and differential Thermogravimetric (DTG) techniques. Thermal analysis results indicated that HQ-Fcs were thermally stable and have better burning rate catalytic effects in accelerating thermal decomposition of AP. Anti-migration behavior of HQ-Fcs in comparison to commonly used 2,2-bis (ethylferrocenyl) propane (catocene) and Fc was evaluated. It was observed that HQ-Fcs delivered excellent anti-migration performances than catocene and Fc.

Fabrication of Si@AP/NC metastable intermixed nanocomposites (MICs) by electrospray method and their thermal reactivity

In order to enhance the heat release of nanoparticles silicon, the Si@AP/NC metastable intermixed composites (MICs) Si@AP/NC with varied content of silicon (40%, 60%, and 80%) were designed and prepared by electrospray. Observation by scanning electron microscopy (SEM) has shown that the morphological characterization of those composites was homogeneously mixed. The thermal properties of those MICs were evaluated by means of DSC-TG techniques. Results show that the low- and high-temperature decomposition of AP transitioned from two separated stages to a one-step process. This was mainly caused by the interaction of thin silica on the surface of silicon and perchloric acid. The dependence of activation energy on the conversation rate was obtained by making use of state-of-the-art kinetic procedures. It has been found that decomposition of Si@NC/AP-40 and Si@NC/AP-60 followed the random chain scission model. With the strengthening of active centers of silica, the mechanism of proton migration of AP turned into the growth of the nucleus. The decomposition process of AP started on the surface of the crystal and gradually decomposed steadily as AP decomposition proceeded. Therefore, it is a first-order reaction model for Si@NC/AP-60 and Si@NC/AP-80 in their second-step reaction. Overall, manufacture spherical Si-NPs composites wrapped in polymer though electrostatic spray technology, a novel way of preparing nanoenergetic materials was created. These nanocomposites could be applied normally as fuels in thermobaric explosives or solid propellants.

Thermal decomposition of ammonium perchlorate/exfoliated-graphene and the relationship between activation energy and band gap

ABSTRACTThe thermal decomposition of ammonium perchlorate AP with electrochemically exfoliated graphene flakes (EGF) was studied at different heating rates in nitrogen and the combustion behavior of AP/EGF propellant was evaluated. The exothermic reaction kinetics were studied by simultaneous thermal analysis (STA) in non-isothermal conditions and compare with the thermal decomposition of pure AP applying the same experimental conditions. Using the Kissinger method, the calculated activation energies Ea for the low- and high-temperature exothermic reactions were 87 and 198 kJ/mol for pure AP, contrasting with 91 and 55 kJ/mol obtained from AP with 5 wt% EGF. From our experimental activation energy values together with reported and calculated band gaps Eg, it was found the empirical relationship:where Ea0 corresponds to the activation energy associated with the high-temperature thermal decomposition of pure AP, Eac is the activation energy associated to the high-temperature thermal decomposition of AP-EGF, E0 = 2.7 eV is the catalyst band gap threshold required to activate the electron transfer mechanism and n = 6 is the exponential factor associated to pure AP.

The catalytic activity of transition metal oxide nanoparticles on thermal decomposition of ammonium perchlorate

Abstract The catalytic proficiency of three MONs for AP thermal decomposition was studied in this work. A chemical co-precipitation method was used for synthesis of MONs (CuZnO, CoZnO, and NiZnO) and their characterization carried out by utilizing XRD, FTIR, and SEM. The TGA/DSC technique was employed for the investigation of the catalytic proficiency of MONs on the AP. The DSC data were used for measuring activation energy of catalyzed AP by using Ozawa, Kissinger, and Starink method. The MONs were much sensitive for AP decomposition, and the performance of AP decomposition was further improved. Among all the MONs, the CuZnO exhibits higher catalytic action than others and decomposition temperature of AP is descending around 117 °C by CuZnO. The reduction in the activation energy was noticed after the incorporation of MONs in AP.

Thermal Decomposition of Ammonium Perchlorate in the Presence of Cobalt Hydroxyl@Nano-Porous Polyaniline

In this report, nanoporous polyaniline (NP-PANi) as an intrinsic conductive polymer (ICPs) was sonochemically synthesized and coated by Cobalt Hydroxyl nanoparticles using precipitation method. The prepared Cobalt Hydroxyl@NP-PANi (CoPANi) merged two separated peaks of AP into a width peak revealed at 297 °C, and drastically increased the area under the peak about 90–334%. Dependency of activation energy (Eα) to the reaction progress (α) was investigated by Starink method and results showed that in the presence of CoPANi throughout the reaction, Eα of AP decomposition was completely shifted to the lower values. The thermal decomposition mechanisms of samples were evaluated by Complementary method using a MATLAB code. The best decomposition reaction model obtained for AP was Avrami Erofeyev (A2) which CoPANi changed it to (A4); this caused Ea reduced from 161 (KJ/mol) to 113 (KJ/mol). Reaction rate constant, pre-exponential factor, Characteristic temperatures (TSADT and Tb) and thermodynamic parameters have been also calculated, the noted parameters presented a descending trend when the CoPANi was used. As the results confirmed the strong modifying effect of Cobalt Hydroxyl@NP-PANi on AP decomposition reaction, this report would be helpful for further application of M(OH)x@ICPs as a new family of burning rate modifier materials used for decomposition of energetic material.

HTPB‐Clay Nanocomposites (HCN): An Efficient Burning Rate Catalyst for Composite Propellant

AbstractIn present study, two types of montmorillonite clay, organically modified with polar and apolar moieties, are used, for preparation of HTPB‐clay nanocomposites (HCN) by dispersion of nanoclay in polymer matrix with high shear mixing. These nanocomposites are evaluated in composite propellants for their catalytic effect on decomposition of ammonium perchlorate a work horse oxidizer. Several composite propellant formulations containing 1–3 weight % of nanoclays over binder, were prepared. Along with this, formulations with conventional burning rate catalyst like iron oxide in 1–3 weight % over binder, and formulation without any burning rate catalyst as base composition were also processed. All these formulations were evaluated by means of theoretical prediction, end of mix viscosity, ballistic properties, mechanical properties, sensitivity parameters and thermophysical properties. Experimental results showed that HCN based compositions have lower or comparable end of mix viscosity than base compositions. Further characterization revealed that formulations with 3 weight % of nanoclays over binder have 70 % higher burning rate than base composition as well as 20–25 % higher burning rate than compositions having 3 weight % of iron oxide over binder. Pressure exponent values are determined for 3 to 11 MPa of pressure range and were found to be significantly higher for HCN based compositions (0.33 to 0.7) in comparison to the base composition. Mechanical properties and sensitivity data of HCN based compositions are comparable with base composition. Thermal studies revealed decrease in onset temperature of decomposition of AP with presence of nanoclay which may be the probable cause for enhancement in burning rate.

Oxidation of Catocene in AP/Catocene Mixture at Low Temperature

AbstractThe mixture of Catocene and fine AP after 175 °C heat treatment was washed by acetone and water, and the washing liquids of acetone and water were characterized by SP and microwave digestion‐ICP, and the solid products were characterized by XPS, XRD, SEM‐EDS. The results show that the oxidation of Catocene is a multi‐step reaction, and the final products are nano‐sized Fe2O3 and amorphous C. DTA‐TG test shows the productions can enhance the thermal decomposition of AP. Compared with the mixture of fine AP and Catocene, the mixture of fine AP and the final solid product of Catocene decomposition is insensitive to the impact. The effective constituents of Catocene catalysis for thermal decomposition of AP are nano‐sized Fe2O3 and amorphous C. Analyzing by synthesis, the final solid product may be an effective and safe catalyst for AP based propellant.

In situ generated 3D hierarchical Co3O4@MnO2 core–shell hybrid materials: self-assembled fabrication, morphological control and energy applications

A new series of highly ordered 3D hierarchical Co3O4@MnO2 core–shell hybrid materials was developed by a simple in situ self-assembly strategy for two typical energy applications in DSSCs and AP decomposition with superior performances.

Controllable synthesis of multi-shelled NiCo2O4 hollow spheres catalytically for the thermal decomposition of ammonium perchlorate.

The compatible catalytic structure of NiCo2O4 was modified into multi-shelled hollow spheres by one-pot synthesis, followed by heat treatment. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer–Emmet–Teller (BET) and N2 adsorption–desorption approaches were used for the characterizations of nanoparticles and multi-shelled hollow porous structures and the morphologies and crystal structures of these hollow spheres, respectively. Differential scanning calorimetry (DSC) was adopted for comparing the thermal decomposition performances of ammonium perchlorate (AP) catalyzed by adding different contents of multi-shelled NiCo2O4 hollow spheres. Impressively, the experimental results showed that the NiCo2O4 hollow spheres exhibited more excellent catalytic activity than NiCo2O4 nanoparticles as a result of their large specific surface areas, good adsorption capacity and many active reduction sites. The decomposition temperature of AP with multi-shelled NiCo2O4 hollow spheres could be reduced up to 322.3 °C from 416.3 °C. Furthermore, a catalytic mechanism was proposed for the thermal decomposition of AP over multi-shelled NiCo2O4 hollow spheres based on electron transfer processes.

Synthesis and Characterization of a Dinuclear Nitrogen‐Rich Ferrocenyl Ligand and Its Ionic Coordination Compounds and Their Catalytic Effects During Combustion

Alkylferrocene‐based burning‐rate catalysts (BRCs) exhibit distinct migration tendency and high volatility and thus result in inferior performance of composite solid propellants during their combustion processes. To deal with these drawbacks, a novel dinuclear nitrogen‐rich ferrocene derivative, 4‐amino‐3,5‐bis(4‐ferrocenyl‐1,2,3‐triazolyl‐1‐methyl)‐1,2,4‐triazole (BFcTAZ) and its twenty seven ionic coordination compounds, [M2(BFcTAZ)2(H2O)4]mXn·xH2O (M = Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+ and Pb2; X = polycyano anions), were synthesized and characterized by FT‐IR, UV/Vis, and elementary analysis. Crystal structure of BFcTAZ was further confirmed by single‐crystal X‐ray diffraction and a general molecular structure of the new complexes was proposed. Their high thermal stability was verified by TG technique. Cyclic voltammetry studies suggested that the new compounds are diverse redox systems. Their effects on the thermal degradation of some common oxidizers were measured by DSC technique. The results indicated that most of the new complexes exert great effects on the thermal decomposition of AP, RDX, and 1,1‐diamino‐2,2‐dinitroethylene (FOX‐7) and some of them are more active than catocene. The Cu2+ complexes are among the excellent ones. However, only six compounds have appreciable catalytic activity in the thermal degradation of HMX.

Synthesis of Nano‐Porous Polyaniline and Investigation its Catalytic Effect on the Thermal Decomposition of Ammonium Perchlorate

AbstractAmmonium perchlorate (AP) is one of the most well‐known oxidizers of solid propellant. In this article, an intrinsic conductive polymer (ICP) is introduced as a green catalyst for thermal decomposition of AP. Activation energy of samples was defined by Kissinger method. A MATLAB code and Complementary method were used to derive the best model of samples decomposition reaction. It was revealed that application of nano‐porous polyaniline (NP‐PANi) changed the model of decomposition reaction of AP from to ; as a drastic raise was observed in the maximum reaction rate, in the range of 264‐430%, at different heating rates. reaction rate constant and pre‐exponential factor were also defined. Characteristic temperatures (TSADT and Tb) have been also determined in order to evaluate the thermal stability of process. Thermodynamic parameters have been also calculated, as the results confirmed the proper catalytic activity of NP‐PANI in AP decomposition process. The obtained results would be helpful for further application of ICPs as a noble family of green catalysts used for decomposition of energetic material.

Comparison of burn rate and thermal decomposition of AP as oxidizer and PVC and HTPB as fuel binder based composite solid propellants

Abstract In the present investigation an effort has been made to understand the thermal decomposition and burn rate characteristics of AP as oxidizer and PVC and HTPB as fuel binder in composite solid propellant. The burning rate study has been carried out at ambient and different pressures of 2.068Mpa, 4.760Mpa, 6.895Mpa. The mechanism of thermal decomposition of each composition have also been determined by NETZSCH simultaneous thermal analyser, comprising differential scanning calorimeter (DSC) and thermo-gravimetric analyser (TGA). An effort has been made to study the burn rate and decomposition of fuel binder and oxidizer in presence of Fe2O3 and also their overall impact on combustion of propellant.

In-situ preparation of MgFe2O4-GO nanocomposite and its enhanced catalytic reactivity on decomposition of AP and RDX

MgFe2O4-GO nanocomposite was successfully prepared by in situ growth method and characterized by XRD, FT-IR, Raman, SEM and TEM. MgFe2O4 nanoparticles were tightly anchored on the surfaces of GO sheets, and no separation of MgFe2O4 from GO sheets was found after ultrasound treatment for 10 min. GO sheets effectively prevent the aggregation of MgFe2O4 nanoparticles, and the particle size of MgFe2O4 is about 80 nm. Catalytic decomposition results show that the MgFe2O4-GO nanocomposite could obviously reduce the decomposition temperature and apparent activation energy of AP from 406.8 to 306.5 °C and from 161.0 to 116.6 kJ mol−1，respectively, and increase the decomposition heat of AP from 654.7 to 1183.2 J g−1. The thermal decomposition temperature of RDX was also reduced from 242.3 to 234.6 °C. MgFe2O4-GO nanocomposite prepared by in situ growth method exhibits better catalytic decomposition performances than pure MgFe2O4, physical mixture MgFe2O4 + GO and self-assembled MgFe2O4/GO.

Catalytic effects of p-phenylene-bridged methylated binuclear ferrocenes on thermal decomposition of the main component of composite solid propellants

This contribution describes the catalytic activity of homobimetallic complexes derived from p-phenylene on the thermal decomposition of ammonium perchlorate (abbreviated as AP). The complexes, [CpFe-p-Ph-FeCp] (1), [Cp*Fe-p-Ph-FeCp*] (2), [CpFe-p-Ph’-FeCp] (3) and [Cp*Fe-p-Ph’-FeCp*] (4) (with p-Ph: p-Bis(3,4-dimethylcyclopentadienyl)benzene and p-Ph’: p-Bis(2,3,4,5-tetramethylcyclopentadienyl)benzene), were compared with the catalytic activity of the catocene (cat) complex previously reported. Furthermore, in order to clarify the mechanism of the bimetallic compounds, it was tested ferrocene (Fc), frequently used as burning rate (BR) catalyst on the thermal decomposition of AP. The synthetized compounds shown a shift on the peak temperature to lower values and an increase in the released heats during thermal decomposition of AP. The burning rate catalytic activity of the compounds on thermal decomposition of AP were examined by thermogravimetry and differential scanning calorimetry techniques. Theoretical calculations of these compounds were carried out to gain further understanding of these catalysts systems.

Catalytic Action of Submicrometer Spherical Ta/Ph‐Fe on Combustion of AP/HTPB Propellant

AbstractThis paper describes the preparation of two combustion catalysts Tannin‐Fe (Ta−Fe) and Phloroglucinol‐Fe (Ph−Fe) by spray drying. The particle size and morphology of the particles are observed by scanning electron microscopy (SEM). The results of SEM image show that the particles are regular spherical and very good dispersion. The diameter of most spherical particles is about 1 μm. The effects of Ta−Fe and Ph−Fe on the thermal decomposition of RDX and AP were tested by differential scanning calorimeter (DSC). DSC dates show that Ta−Fe and Ph−Fe can advance the high temperature exothermic peak of AP 18.0 °C and 16.1 °C, respectively. The burning rates illustrates that both Ta−Fe and Ph−Fe can significantly increase the combustion rate of HTPB propellants. The formulation with 2 mass% Ta−Fe shows an average 21.31 % increase in burning rate and has a low value of the exponent n=0.48. The formulation with 2 mass%Ph−Fe has a burning rate 20 to 60 % larger than that of the initial AP/HTPB/Al formulation, and has a lowest exponent n=0.45.

Study on Thermal Behaviour of AP/LiBH4 Energetic System

AbstractAmmonium perchlorate(AP) and LiBH4 can form an oxidation‐fuel energetic system, which provides a new development direction in designing novel mixed explosive formula. The microcalorimetry and self‐designed slow cook‐off setup were used to study thermal performance of AP/LiBH4 energetic powders and grains respectively. Experimental results show that heat release in microcalorimetry method for the mixed system at low temperature was due to the reaction between LiBH4 and residual water vapour. The oxidant gases from AP decomposition participate in the oxidation of LiBH4 at high temperature. The ignition temperature for the AP/LiBH4 grain was 270 °C and the explosion reactions were violent in slow cook‐off test.

Facile synthesis of flower-like ZnO@Fe2O3 hierarchical nanostructures with enhanced catalytic activity on the thermal decomposition of ammonium perchlorate

This paper reports a facile two-step hydrothermal method for the fabrication of f-ZnO@Fe2O3 nanostructures. Various characterization results show that the hierarchical nanocomposites are formed by the loading of well-crystallized α-Fe2O3 nanoparticles onto the flower-like ZnO. The nanostructures exhibit large specific surface area and narrow mesoporous size distribution. Morphological measurements indicate that Fe2O3 nanoparticles are densely and uniformly attached onto the entire surface of the f-ZnO. The catalytic performance of the f-ZnO@Fe2O3 on the thermal decomposition of AP is measured by TG and DTA methods. The results demonstrate that the f-ZnO@Fe2O3 nanostructures can lower the decomposition temperature and accelerate the decomposition process of ammonium perchlorate, which may be presumably ascribed to the synergistic effect between f-ZnO and α-Fe2O3 nanoparticles.

Investigation of simultaneous formation of nano-sized CuO and ZnO on the thermal decomposition of ammonium perchlorate for composite solid propellants

Core/shell composites of CuC2O4·2H2O@AP and ZnC2O4·2H2O@AP were prepared from metal oxalates on suspended AP particles in ethanol. CuO and ZnO nano-metal oxides as the nano-catalysts were made from CuC2O4·2H2O and ZnC2O4·2H2O simultaneously by thermal decomposition of AP. The particle size of CuO nano-particles was very finer, and the ZnO particles showed a considerable growth during formation. The kinetic triplet of activation energy, frequency factor, and model of thermal decomposition of pure AP, CuC2O4·2H2O@AP, and ZnC2O4·2H2O@AP composites were estimated by applying three model-free (FWO, KAS, and Starink) and model-fitting (Starink) methods. Based on the thermal analysis, the CuC2O4@AP composite has better catalytic performance and the thermal decomposition temperature of AP decreased to about 126.44 °C.

Visible light-enhanced thermal decomposition performance of ammonium perchlorate with a metal–organic framework-derived Ag-embedded porous ZnO nanocomposite

An Ag-embedded porous ZnO nanocomposite (Ag–ZnO NC) fabricated using an MOF exhibits high catalytic activity for the thermal decomposition of AP under the assistance of visible light.

Energetic Nanocomposites as Burn Rate Catalyst for Composite Solid Propellants

AbstractIn the present study the effect of addition of Al/Fe2O3 based energetic nanocomposites (ENC) to non‐aluminized and aluminized propellants was investigated. Comparative study was carried out using n‐Fe2O3 as burn rate catalyst. Ferric oxide xerogel and Al/Fe2O3 ENC were synthesized by sol‐gel method. The dried xerogel was characterised by Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X‐ray diffraction (XRD) and X‐ray photoelectron spectroscopy (XPS). TEM and SEM images reveal presence of porous interconnected ferric oxide clusters of size 3–5 nm and intimate mixing of the ingredients at nanoscale in case of ENC. XRD analysis shows amorphous nature of the ferric oxide xerogel. Fe2O3 and FeO(OH) are the major constituents (>84 %) of the xerogel as confirmed by XPS analysis. Thermal analysis of the ENC indicates that the composition is energetic in nature. Sensitivity analysis was carried out to assess the safety of the ENC during propellant processing. The differential scanning calorimetry (DSC) results for propellant samples show that the Al/Fe2O3 ENC is a better catalyst for AP decomposition than n−Fe2O3. Burn rate studies of ENC catalyzed propellants with μ‐Al and with n‐Al were carried out using acoustic strand burner. The results indicate that ENCs can be promising catalysts for composite propellants.