Thermokinetic Investigation of the Aluminum Nanoparticles Oxidation

Vorozhtsov, Alexander; Rodkevich, Nikolay; Bondarchuk, Ivan S.; Лернер, М. И.; Жуков, А. С.; Глазкова, Е. А.; Бондарчук, С. С.

doi:10.1615/intjenergeticmaterialschemprop.2018022010

Cited by 6 publications

(5 citation statements)

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“…of Equation (7) is non-elementary and cannot be determined analytically. A number of studies that estimated the value of this temperature integral proposed different techniques and approximations and included many references (e.g., [ 1 , 2 , 5 , 6 , 10 , 14 , 25 , 26 , 27 ]).…”

Section: Results Of Theoretical Analysis— Proposed Approachmentioning

confidence: 99%

“…Over the last 50 years, a large number of studies have discussed improving the accuracy of approximations of the temperature integral (the integral of the Arrhenius function), which does not have an analytical expression. Infinite series, rational and special functions, series of Chebyshev polynomials, and approximations obtained directly from numerical solutions are used to approximate the values of the integral [ 1 , 2 , 5 , 6 , 10 , 14 , 25 , 26 , 27 ]. At present, according to the literature, the proposed approximations and approaches associated with them are less significant, since the solution of the corresponding inverse problems of chemical kinetics is usually performed on a computer, and the exact numerical calculation of temperature integral [ 28 ] is easily included into the algorithms for solving inverse problems of kinetics.…”

Section: Introductionmentioning

confidence: 99%

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Advanced Fitting Method for the Kinetic Analysis of Thermogravimetric Data

et al. 2023

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The article considered the solution of the inverse problem of chemical kinetics of the analysis of experimental data of a thermogravimetric experiment at a constant sample heating rate. The fitting method for identifying the parameters of a kinetic triplet using the integral method for a model of a solid-state reaction based on the modified Arrhenius equation is described. The effectiveness of the proposed approach was confirmed by solving test cases for low, medium, and high rates of material conversion. Unlike other methods, setting the parameters of the reaction mechanism is not required, as they are determined by the solution. Solutions for real data of TGA studies with high and low sample heating rates were compared with the results obtained by other authors and experimental data. A description of the full cycle of calculations used to identify kinetic parameters from thermogravimetric experimental data is given, from the derivation of calculated relationships to the implementation of a short (three to five formulas) program code for MS Excel spreadsheets. The presented code is easy to verify and reproduce and can be modified to solve various problems.

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Section: Results Of Theoretical Analysis— Proposed Approachmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Advanced Fitting Method for the Kinetic Analysis of Thermogravimetric Data

et al. 2023

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“…The first stage is the disruption of nAl particle clusters when stirring with acetylacetone and formation of the organic chemisorbed layer on the nanoparticle surface. This layer increases the hydrophobicity and compatibility with the polymer of the nanoparticle surface and facilitates the sorption of the HTPB molecules [31]. The second stage is the application of HTPB on the nanoparticle surface.…”

Section: Discussionmentioning

confidence: 99%

“…So the HTPB destruction proceeds and aluminum oxidation sequential reactions occurring independently of each other. The thermal degradation of HTPB in the nAl/HTPB pastes at the second stage proceeds in the same temperature range as that of HTPB [31]. The degradation proceeding at this stage can be assumed to be noncatalytic process.…”

Section: Discussionmentioning

confidence: 99%

Preparation and Characterization of Al/HTPB Composite for High Energetic Materials

et al. 2020

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Nanosized Al (nAl) powders offer increased reactivity than the conventional micron-sized counterpart, thanks to their reduced size and increased specific surface area. While desirable from the combustion viewpoint, this high reactivity comes at the cost of difficult handling and implementation of the nanosized powders in preparations. The coating with hydroxyl-terminated polybutadiene (HTPB) is proposed to improve powder handling and ease of use of nAl and to limit its sensitivity to aging. The nAl/HTPB composite can be an intermediate product for the subsequent manufacturing of mixed high-energy materials while maintaining the qualities and advantages of nAl. In this work, experimental studies of the high-energy mixture nAl/HTPB are carried out. The investigated materials include two composites: nAl (90 wt.%) + HTPB (10 wt.%) and nAl (80 wt.%) + HTPB (20 wt.%). Thermogravimetric analysis (TGA) is performed from 30 to 1000 °C at slow heating rate (10 °C/min) in inert (Ar) and oxidizing (air) environment. The combustion characteristics of propellant formulations loaded with conventional and HTPB-coated nAl are analyzed and discussed. Results show the increased burning rate performance of nAl/HTPB-loaded propellants over the counterpart loaded with micron-sized Al.

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“…In past works, approximations of this integral have been approached using various techniques, such as infinite series, rational and special functions, Chebyshev polynomial series, and other approximations obtained directly from the numerical solutions. [10][11][12][13][14][15][16][17][18] However, according to current literature, these approximations and associated approaches are less relevant than the specific problems of chemical kinetics; they are typically solved using computers, where the exact numerical calculation of the temperature integral can be easily incorporated into the algorithms. [19,20] In this work, a linear approximation in x and a reciprocal cubic polynomial approximation in x will be used, with errors of less than 0.4% for the linear approximation in the interval −50 ≤ x ≤ −21, and less than 0.032% for the polynomial approximation in the interval −200 ≤ x ≤ −15.…”

Section: Chemical Kinetics and Its Application In The Study Of Pp The...mentioning

confidence: 99%

Improvement of the Mathematical Model for Quality Assurance in the Determination of Kinetic Parameters of Thermal Degradation of Polypropylene Through Thermogravimetric Analysis

Fregoso‐Israel,

Olvera‐Treviño,

Romero‐Hernández

et al. 2023

Macro Theory & Simulations

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A robust mathematical treatment of the Ozawa/Flynn/Wall isoconversion method is conducted to determine the value and uncertainty of the activation energy and pre‐exponential factor for the degradation of polypropylene (PP) in thermogravimetric analysis (TGA) experiments at constant heating rates. In the present work are employed mathematical models and uncertainty propagation techniques, based on the Guide to the Expression of Uncertainty in Measurement (GUM) to estimate the Arrhenius activation energy and preexponential factor due the uncertainty of the integration constant b, both in a linear and a third‐degree reciprocal polynomial model with respect to x. The error arising from Doyle's linear approximation in the improper integral of temperature in the Arrhenius equation is examined, and an alternative method is proposed to correct this error, reducing it to 0.032% in the working interval of ̶ 200 ≤ x ≤ ̶ 15, where x = ̶ E/RT. Given the increased sensitivity of modern TGA equipment, these improvements are considered essential for obtaining reliable results that align with experimental precision limits compared to previous works. Thus, this allows for the development of an enhanced quality assurance framework by providing a more robust uncertainty estimation and better understanding of the method, leading to more reliable results. Moreover, this approach can be applied to other similar polymer systems.This article is protected by copyright. All rights reserved

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Thermokinetic Investigation of the Aluminum Nanoparticles Oxidation

Cited by 6 publications

References 0 publications

Advanced Fitting Method for the Kinetic Analysis of Thermogravimetric Data

Advanced Fitting Method for the Kinetic Analysis of Thermogravimetric Data

Preparation and Characterization of Al/HTPB Composite for High Energetic Materials

Improvement of the Mathematical Model for Quality Assurance in the Determination of Kinetic Parameters of Thermal Degradation of Polypropylene Through Thermogravimetric Analysis

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