Model-free and model-fitting approaches to kinetic analysis of isothermal and nonisothermal data

Vyazovkin, Sergey; Wight, Charles A.

doi:10.1016/s0040-6031(99)00253-1

Cited by 1,251 publications

(665 citation statements)

References 45 publications

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“…31,32 During this process the experimental data are compared with the simulated ones, which occur from the use of different kinetic models. During the model-fitting process, the samples were heated with 3 different heating rates (5, 10, 20 1C min À1 ).…”

Section: View Article Onlinementioning

confidence: 99%

Thermal degradation kinetics and decomposition mechanism of PBSu nanocomposites with silica-nanotubes and strontium hydroxyapatite nanorods

Roumeli

Chrissafis

Lioutas

et al. 2014

Phys. Chem. Chem. Phys.

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Novel poly(butylene succinate) (PBSu) nanocomposites containing 5 and 20 wt% mesoporous strontium hydroxyapatite nanorods (SrHNRs) and silica nanotubes (SiNTs) were prepared by melt-mixing. A systematic investigation of the thermal stability and decomposition kinetics of PBSu was performed using pyrolysis-gas chromatography-mass spectroscopy (Py-GC-MS) and thermogravimetry (TG). Thorough studies of evolving decomposition compounds along with the isoconversional and model-fitting analysis of mass loss data led to the proposal of a decomposition mechanism for PBSu. Moreover, the effects of SrHNRs and SiNTs on the thermal stability and decomposition kinetics of PBSu were also examined in detail. The complementary use of these techniques revealed that the incorporation of SiNTs in PBSu does not induce significant effects neither on its thermal stability nor on its decomposition mechanism. In contrast, the addition of SrHNRs resulted in the catalysis of the initial decomposition steps of PBSu and also in modified decomposition mechanisms and activation energies. The evolving gaseous products of PBSu and their evolution pattern in the SiNT nanocomposites were the same as in neat PBSu, while they were slightly modified for the SrHNR nanocomposites, confirming the findings from thermogravimetric analysis.

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Section: View Article Onlinementioning

confidence: 99%

Thermal degradation kinetics and decomposition mechanism of PBSu nanocomposites with silica-nanotubes and strontium hydroxyapatite nanorods

Roumeli

Chrissafis

Lioutas

et al. 2014

Phys. Chem. Chem. Phys.

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show abstract

“…And, the operation can be operated in both isothermal [3]- [5] and non-isothermal [5]- [11]. For the isothermal operation, sample temperature is initially increased rapidly from room temperature to a specific temperature and maintained at that temperature for an entire degradation process.…”

Section: Introductionsmentioning

confidence: 99%

“…Calculation methods for kinetic parameters from the TG curve can be divided into 2 classes, a model-fitting method and a model-free method, which can be used for the isothermal and the non-isothermal conditions [3]. A feature of the model-fitting method is that, based on rate equation and Arrhenius equation, this method requires an assumption of a reaction model before activation energy and a frequency factor can be interpreted.…”

Section: Introductionsmentioning

confidence: 99%

“…Therefore, the model-free method can be recommended as a trustworthy way to obtain the reliable and consistent kinetic information from the non-isothermal condition. And, it can help to reveal a complexity of multiple reactions due to the dependencies of the activation energy on the extent of the conversion [3], [6], [12].…”

Section: Introductionsmentioning

confidence: 99%

“…Considering the non-isothermal model-free method, there are different types of the temperature integral numerical approximation approaches for example Ozawa, Flynn and Wall (OFW) method using a linear approximation (less accurate) utilizing Doyle's approximation [9] and Vyazovkin (VYZ) method using a non-linear approximation (more accurate) [3] utilizing a direct numerical integration method [11], Cai et al approximation [5], Coats & Redfern approximation, Gorbachev approximation or Agrawal and Sivasubramanian approximation [6]. Between OFW method and VYZ method, VYZ model-free method has become popular because it can bring out the more reliable and consistent kinetic information from the non-isothermal TG data of the polymer degradation [11].…”

Section: Introductionsmentioning

confidence: 99%

See 2 more Smart Citations

Kinetic Analysis of Thermal Degradation of Polyolefin Mixtures

Murichan¹,

Cherntongchai²

2014

IJCEA

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Abstract-Plastic wastes are a global concern for their environmental impacts. A proficiency method for plastic waste management is a chemical recycling through a pyrolysis process. In this work, kinetic analysis of thermal degradation of polyolefin mixture between polypropylene (PP) and low density polyethylene (LDPE) under pyrolysis atmosphere at different compositions was investigated using thermogravimetric analysis (TGA), operated non-isothermally. Besides, Vyazovkin model-free method, together with different temperature integral approximation approaches, was used for kinetic parameter analysis from TGA results. It was found that thermal degradation process of polyolefin mixture was a triple step process and an addition of PP reduced degradation temperature. Besides, different approximation approaches did not affect activation energy value. For polyolefin mixture, the activation energy was increased initially, constant intermediately and finally increased again with increasing conversion. Finally, the activation energy of the polyolefin mixture was lower than those of pure polymers and decreased with increasing PP fraction.

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Thermogravimetric Analysis

Vyazovkin

2012

Characterization of Materials

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Thermogravimetric analysis (TGA) is an analytical technique for measuring changes in the mass of a material that occur in response to programmed temperature changes. The changes in the mass can be caused by a variety processes such as decomposition, degradation, sublimation, vaporization, adsorption, desorption, oxidation, and reduction. The article explains the principles of TGA and practical aspects of the method that include description of the apparatus, discussion of experimental variables, and applications. Among practical applications, a particular attention is paid to determining composition and thermal stability of materials, evaluating the kinetics of thermally stimulated processes, predicting lifetimes, and studying reactions of materials with gases. The article also addresses the issues of sample preparation as well as of basic analysis and interpretation of data. A special consideration is given to the sources of errors in the mass and temperature measurements as well as to the methods of calibrating both values.

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Model-free and model-fitting approaches to kinetic analysis of isothermal and nonisothermal data

Cited by 1,251 publications

References 45 publications

Thermal degradation kinetics and decomposition mechanism of PBSu nanocomposites with silica-nanotubes and strontium hydroxyapatite nanorods

Thermal degradation kinetics and decomposition mechanism of PBSu nanocomposites with silica-nanotubes and strontium hydroxyapatite nanorods

Kinetic Analysis of Thermal Degradation of Polyolefin Mixtures

Thermogravimetric Analysis

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