Kinetic analysis of derivative curves in thermal analysis
01 Sep 1970-Journal of Thermal Analysis and Calorimetry (Akadémiai Kiadó, co-published with Springer Science+Business Media B.V., Formerly Kluwer Academic Publishers B.V.)-Vol. 2, Iss: 3, pp 301-324
TL;DR: In this article, two methods of obtaining kinetic parameters from derivative thermoanalytical curves are proposed based on the general form of kinetic formulae and are applicable to general types of reactions governed by a single activation energy.
Abstract: Two methods of obtaining kinetic parameters from derivative thermoanalytical curves are proposed The methods are based on the general form of kinetic formulae and are applicable to general types of reactions governed by a single activation energy One method utilizes the linear relation between peak temperature and heating rate in order to estimate the activation energy, and only the information of the rate of conversion versus the temperature is necessary The other method needs the information of both the conversion and the rate of conversion versus the temperature, and the Arrhenius plot is made for an assumed kinetic mechanism
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TL;DR: In this article, a classification of model-free isoconversion methods for the calculation of activation energies of thermally activated reactions is proposed, by deriving expressions for the main sources of error which includes the inaccuracy in reaction rate measurement, approximations for the temperature integral and inaccuracies in determination of temperature for equivalent fraction transformed.
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TL;DR: A critical review of kinetic models and mathematical approximations currently employed in solid state thermal analysis is provided and analysis of thermal decomposition data obtained from two agricultural residues, nutshells and sugarcane bagasse reveals the inherent difficulty and risks involved in modeling heterogeneous reaction systems.
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TL;DR: The results of the ICTAC Kinetics Project as mentioned in this paper have been used to forecast the tendencies for the future development of solid state kinetics, as well as the findings of the participants are compared.
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TL;DR: In this article, a simple method of kinetic analysis of thermal analysis (TA) data is described, which allows one to find the appropriate model characterizing the process studied as well as the calculation of the kinetic parameters.
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TL;DR: A review of previously suggested methods for analysis of experimental data of non-isothermal crystallization kinetics based on the Johnson-Mehl-Avrami transformation rate equation is given in this paper.
Abstract: A brief review is given of previously suggested methods for analysis of experimental data of non-isothermal crystallization kinetics based on the Johnson-Mehl-Avrami transformation rate equation. Conditions for applicability are outlined and an estimate of error is made. A method of non-isothermal analysis is presented which facilitates rapid data evaluation over large temperature ranges and which justifies the previous applications in the literature of Kissinger's method to the analysis of crystallizations kinetics. An extension of these methods is made to the case of growth rates which obey a Vogel-Further temperature relation.
678 citations
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10,842 citations
TL;DR: In this paper, a new method of obtaining the kinetic parameters from thermogravimetric curves has been proposed, which is simple and applicable to reactions which can not be analyzed by other methods.
Abstract: A new method of obtaining the kinetic parameters from thermogravimetric curves has been proposed. The method is simple and applicable to reactions which can not be analyzed by other methods. The effect of the heating rate on thermogravimetric curves has been elucidated, and the master curve of the experimental curves at different heating rates has been derived. The applications of the method to the pyrolyses of calcium oxalate and nylon 6 have been shown ; the results are in good agreement with the reported values. The applicability of the method to other types of thermal analyses has been discussed, and the method of the conversion of the data to other conditions of temperature change has been suggested. From these discussions, the definition of the thermal stability of materials has been criticized.
5,622 citations
1,964 citations
01 Nov 1966-Journal of Research of the National Bureau of Standards Section A: Physics and Chemistry
TL;DR: It is concluded that methods involving a variable rate of heating or involving several thermogravimetric traces at different rates of heating are capable of establishing the uniqueness of kinetic parameters.
Abstract: Theoretical equations are developed for typical decompositions of polymers including those in which the volatilization does not follow a simple "reaction order" and those made up of a composite of several reactions of differing energies of activation. The effects of order, activation energy, heating rate and temperature dependence upon the calculated thermograms is illustrated. The literature on thermogravimetric kinetics is critically reviewed and coalesced into a logical and coherent development stressing the interrelation of methods and employing a consistent system of notation. As a result, a number of improved methods and new methods for the analysis of kinetic data applicable to the complex systems mentioned above are developed. It is concluded that methods involving a variable rate of heating or involving several thermogravimetric traces at different rates of heating are capable of establishing the uniqueness of kinetic parameters. A new method of determining initial parameters from rate-conversion data is developed. A novel concept is employed of programming reaction variables (in this case, the heating rate) in a manner which greatly simplifies the mathematics of the kinetic system and which shows promise of a wide range of applicability in the area of rate processes.
1,644 citations