Applications of sample-controlled thermal analysis (SCTA) to kinetic analysis and synthesis of materials

Pérez‐Maqueda, Luis A.; Criado, J. M.; Jiménez, Pilar; Diánez, M. J.

doi:10.1007/s10973-014-4176-6

Cited by 9 publications

(5 citation statements)

References 89 publications

(30 reference statements)

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“…The latter can be defined for a nonlinear heating program that, in principle, affords extending the Kissinger method beyond the standard linear heating [19]. This is important in connection with the sample controlled thermal analysis [20], in which the temperature program is controlled by the response of the reaction rate to heating. This idea is implemented commercially in the techniques of high or maximum resolution TGA.…”

Section: Of 18mentioning

confidence: 99%

Kissinger Method in Kinetics of Materials: Things to Beware and Be Aware of

Vyazovkin

2020

Molecules

192

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The Kissinger method is an overwhelmingly popular way of estimating the activation energy of thermally stimulated processes studied by differential scanning calorimetry (DSC), differential thermal analysis (DTA), and derivative thermogravimetry (DTG). The simplicity of its use is offset considerably by the number of problems that result from underlying assumptions. The assumption of a first-order reaction introduces a certain evaluation error that may become very large when applying temperature programs other than linear heating. The assumption of heating is embedded in the final equation that makes the method inapplicable to any data obtained on cooling. The method yields a single activation energy in agreement with the assumption of single-step kinetics that creates a problem with the majority of applications. This is illustrated by applying the Kissinger method to some chemical reactions, crystallization, glass transition, and melting. In the cases when the isoconversional activation energy varies significantly, the Kissinger plots tend to be almost perfectly linear that means the method fails to detect the inherent complexity of the processes. It is stressed that the Kissinger method is never the best choice when one is looking for insights into the processes kinetics. Comparably simple isoconversional methods offer an insightful alternative.

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Section: Of 18mentioning

confidence: 99%

Kissinger Method in Kinetics of Materials: Things to Beware and Be Aware of

Vyazovkin

2020

Molecules

192

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“…In addition, the temperature profile during the reaction under controlled rate conditions exhibited a smooth concave shape independent of the applied controlled mass-loss rate C (Figure b). The temperature profile behavior under CRTA conditions is thought to reflect the reverse side of the kinetic behavior of the sigmoidal mass-loss curve at constant temperature. , …”

Section: Resultsmentioning

confidence: 99%

“…To analyze the kinetics of the thermal decomposition, the mass-loss curves were recorded using a suspended-type TG (TGA-50M, Shimadzu Co.) in flowing N 2 (80 cm 3 min –1 ). For each measurement, approximately 5.0 mg of dried SPC granules weighed in a platinum pan (6 mm in diameter and 2.5 mm in depth) was heated using three different modes: isothermal, linear nonisothermal, and controlled transformation rate thermal analysis (CRTA). , After heating the sample to programmed temperatures at β = 10 K min –1 , isothermal mass-loss traces were recorded at different constant temperatures T (383 ≤ T ≤ 413 K). The linear nonisothermal measurements were performed at different β (1 ≤ β ≤ 10 K min –1 ).…”

Section: Methodsmentioning

confidence: 99%

Multistep Kinetic Behavior of the Thermal Decomposition of Granular Sodium Percarbonate: Hindrance Effect of the Outer Surface Layer

2015

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The kinetics and mechanism of the thermal decomposition of granular sodium percarbonate (SPC), which is used as a household oxygen bleach, were studied by thermoanalytical measurements under systematically changing conditions and morphological observation of the reactant solids at different reaction stages. A physico-geometrical kinetic behavior of the reaction that occurs in a core-shell structure composed of an outer surface layer and internal aggregates of SPC crystalline particles was illustrated through detailed kinetic analyses using the kinetic deconvolution method. Simultaneously, the hazardous nature of SPC as a combustion improver was evaluated on the basis of the kinetic behavior of the thermal decomposition. It was found that the outer surface layers of the SPC granules hinder the diffusional removal of product gases generated by the thermal decomposition of the internal SPC crystalline particles. The reaction rate decelerates because of an increase in the internal gaseous pressure as the reaction advances. However, the reaction rate accelerates once crack formation occurs in the outer surface layer at the midpoint of the reaction. Therefore, the overall reaction was empirically demonstrated to consist of two overlapping reaction steps owing to the changes in the self-generated reaction conditions in the interior of the SPC granules.

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“…6b) as in sample A. The possible feature of the partially overlapping two-step process is more clearly seen from the results of the SCTA measurements because of its higher potential of experimental resolution for partially overlapping multistep processes in comparison with conventional thermal analysis [49][50][51]. Figure 7 shows the results of the SCTA measurements.…”

Section: Thermal Behaviorsmentioning

confidence: 93%

Kinetic characterization of multistep thermal oxidation of carbon/carbon composite in flowing air

Nishikawa

Ueta

Hara

et al. 2016

J Therm Anal Calorim

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Thermal oxidation of carbon/carbon composites in an oxidizing atmosphere is a multistep process regulated by the intrinsic heterogeneity of the solid-gas reaction, the additional heterogeneity of the compositional and structural characteristics of the composite, and how these two properties change as the reaction progresses. By focusing on the overlapping features of the component reaction steps, the kinetic characterization of the multistep kinetic process was studied to reveal the correlation between the thermal oxidation behavior and the compositional and structural characteristics of carbon/carbon composites. Using commercially available mechanical pencil leads as a typical model system for a carbon/carbon composite, the thermal behaviors of two different leads manufactured by different companies were investigated comparatively via thermoanalytical techniques and morphological observations. On the basis of a reaction model considering the different reactivities of the main (graphite) and secondary (carbonized polymer) carbon components, the kinetic features of two partially overlapping reaction steps were revealed via a kinetic deconvolution analysis of the thermoanalytical data for the thermal oxidation process. The kinetic results were correlated with the compositional and structural characteristics of carbon/carbon composites using morphological observations of the partially reacted samples. Herein, the practical usefulness of the kinetic analysis in characterizing carbon/carbon composites is discussed.

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Applications of sample-controlled thermal analysis (SCTA) to kinetic analysis and synthesis of materials

Cited by 9 publications

References 89 publications

Kissinger Method in Kinetics of Materials: Things to Beware and Be Aware of

Kissinger Method in Kinetics of Materials: Things to Beware and Be Aware of

Multistep Kinetic Behavior of the Thermal Decomposition of Granular Sodium Percarbonate: Hindrance Effect of the Outer Surface Layer

Kinetic characterization of multistep thermal oxidation of carbon/carbon composite in flowing air

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