Frequent flaws encountered in the manuscripts of kinetic papers

Šimon, Peter; Dubaj, Tibor; Cibulková, Zuzana

doi:10.1007/s10973-022-11436-y

Cited by 14 publications

(4 citation statements)

References 29 publications

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“…Activation energies can be compared validly if the pre-exponential factor for all curing reactions is identical [8]. The result concerning the rate of reaction should be taken from another kinetic parameter such as reaction rate or exothermic peak temperature [8] The curing process of thermosetting polymer is the series of chemical reactions that leads to the formation of a highly crosslinked 3D network [9]. The curing stage starts from a liquid state, where the monomer will react with the hardener/curing agent.…”

Section: Fig 2 Activation Energy (Ea) Determination By Kissinger Methodsmentioning

confidence: 99%

Curing Kinetics of Epoxy Adhesive by Non-Isothermal DSC

Dewi,

Sutrisna,

Supriyatno

et al. 2024

MSF

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Non-isothermal DSC has been used to investigate the curing kinetics of epoxy adhesives (DGEBA-cycloaliphatic amine). The epoxy samples were scanned on DSC with five heating rates (5°C/min, 7.5°C/min, 10°C/min, 12.5°C/min, and 15°C/min). The curing kinetics were obtained through ASTM standards E2890 and E698 (the Ozawa and Kissinger methods). The kinetic parameters obtained include Ea (activation energy), A (pre-exponential factor), and n (reaction order). The activation energy calculated from the Kissinger and Ozawa method was slightly different but insignificant. The reaction rate (dα/dt) and degree of curing/conversion (α) relationship towards temperature (T), and time (t) was also investigated. The curing process's reaction rate (dα/dt) has maximum value; it can no longer increase after a specific conversion rate (α).

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Section: Fig 2 Activation Energy (Ea) Determination By Kissinger Methodsmentioning

confidence: 99%

Curing Kinetics of Epoxy Adhesive by Non-Isothermal DSC

Dewi,

Sutrisna,

Supriyatno

et al. 2024

MSF

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“…Šimon is very careful about the sense of determining activation parameters in each case, because 'what is the structure of the activated complex in case of complex processes?' [78]. In turn, Khrapunow [32] believes that according to known methods of determination, the activation enthalpy can be accepted, but the entropy is controversial.…”

Section: Final Remarksmentioning

confidence: 99%

“…In their book publications, Vyazovkin [79] discusses the Lumry-Eyring law, while Šesták [80] devotes more attention to the discussion related to the Arrhenius vs. non-Arrhenius relationship than to the Eyring equation. Against the background of these books and issues in terms of [29,30,78,81], the issue of TST is an extremely important issue in relation to the classical Arrhenius equation, at the same time emphasizing the aspect of modernity. Nevertheless, against the background of the cited considerations, this work seems to be justified, although it in no way solves the doubts related to TST.…”

Section: Final Remarksmentioning

confidence: 99%

Elements of Transition-State Theory in Relation to the Thermal Dissociation of Selected Solid Compounds

Mianowski,

Radko,

Bigda

2024

Energies

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An analysis was carried out on the thermal dissociation of selected inorganic salts according to Transition-State Theory (TST). For this purpose, two possibilities were compared in the context of rate constants: in the first case using the Arrhenius constant directly from TST, and in the second, using the thermodynamic equilibrium constant of the reaction/process of active state formation. The determined relationships are presented in the form of temperature profiles. It was established that TST applies to reactions for which there is a formally and experimentally reversible reaction, in the literal sense or catalytic process. The importance of the isoequilibrium temperature, which results from the intersection of the thermodynamic temperature profile and the Gibbs free energy of activation, was demonstrated. Its values close to the equilibrium temperature are indicative of more dynamic kinetic qualities. As part of the discussion, the Kinetic Compensation Effect (KCE) was used to observe changes in the entropy of activation by comparing two kinetic characteristics of the same reaction. Enthalpy–Entropy Compensation (EEC) was shown to be the same law as KCE, just expressed differently. This was made possible by TST, specifically the entropy of activation at isokinetic temperature, by which the perspective of the relationship of energy effects changes.

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“…Besides, the reliability of the employed methods and the obtained results was also carefully tested. This is a crucial point in all evaluations of experiments [34]. However, the methods of the mathematical statistics are not…”

Section: Introductionmentioning

confidence: 99%

Kinetics of the CO2 gasification of woods, torrefied woods, and wood chars. Least squares evaluations by empirical models

Várhegyi

Wang

Skreiberg

2023

J Therm Anal Calorim

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The gasification kinetics of chars forming from biomass materials was studied by kinetic equations of type dX/dt = Af(X) exp(− E/(RT)) where X is the conversion of the sample, A is the pre-exponential factor, E is the activation energy and f(X) is a suitable model function. The theoretically deduced f(X) models in the literature are rarely applicable for chars of biomass origin because of chemical and physical inhomogeneities and irregularities. Hence, empirical f(X) functions were determined by a method proposed four years ago (Várhegyi in Energy Fuels 33:2348–2358, 2019). The parameters of the models were obtained by the method of least squares. Thermogravimetric experiments from an earlier work were reevaluated to explore the possibilities of the approaches employed. The experiments belonged to untreated birch and spruce woods; torrefied woods; chars prepared at a higher temperature; and chars formed at high heating rates (ca. 1400 °C min−1). Common kinetic features were found for the CO2 gasification of the chars studied. The reliability of the results was carefully tested by evaluating smaller and larger groups of the experiments and comparing the results. The method proved to be suitable for the determination of realistic f(X), E, and A from single modulated experiments, too. The models described well the gasification of chars forming from different woods through a wide range of temperature programs and thermal pretreatments.

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Frequent flaws encountered in the manuscripts of kinetic papers

Cited by 14 publications

References 29 publications

Curing Kinetics of Epoxy Adhesive by Non-Isothermal DSC

Curing Kinetics of Epoxy Adhesive by Non-Isothermal DSC

Elements of Transition-State Theory in Relation to the Thermal Dissociation of Selected Solid Compounds

Kinetics of the CO2 gasification of woods, torrefied woods, and wood chars. Least squares evaluations by empirical models

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