A variety of isoconversional and model fitting approaches, all of which use multiple heating schedules, are used to analyze
selected data from the ICTAC kinetics and lifetime projects as well as additional simulated data sets created for this work.
The objective is to compare the accuracy and suitability of various approaches for various types of chemical reactions. The
various simulated data sets show that model fitting and isoconversional methods have comparable reliability for extrapolation
outside the range of calibration. First, there is as much variability in prediction for various isoconversional methods as
there is between isoconversional methods as a group and different plausible explicit models. Of the three isoconversional
models investigated, the Friedman method is usually the most accurate. This is particularly true for energetic materials that
have a drop in apparent activation energy in the latter stages of reaction, which leads to a delayed onset of rapid autocatalysis
at lower temperatures. It is difficult to determine a priori whether isoconversional or model fitting approaches will give
more accurate predictions. The greatest reliability is attained by using both the isoconversional and model fitting approaches
on a combination of isothermal and constant heating rate data.
Temperature programmed combustions (TPC) of Yang-Quan anthracite, Liao-Cheng lean coal and Li-Yan bituminous coal in oxy-fuel
atmosphere were conducted in a thermogravimetric analyzer and characteristic parameters were deduced from the TG-DTG curves.
The results showed that combustion got harder to progress as the coalification degree increasing. Within range of 40%, effect
of heightening O2 concentration favored the combustion process, but beyond this zone, the effect leveled off. The model-fitting mathematical
approach was used to evaluated the kinetic triplet (f (α), E, A) through Coats–Redfern method. The calculation showed that D3-Jander was the proper reaction model and the evaluations of E and A validated the experimental results.
Thermal decomposition of cellulose has been widely studied for the past several years. It has been reported that the source
of cellulose and its composition greatly affect its pyrolysis. One of the most widely used analytical tools for the study
of cellulose pyrolysis is thermogravimetric (TG) analysis. Several model-fitting methods have been employed to study cellulose
pyrolysis kinetics. An alternative to the model-fitting approach is the so-called model-free method developed by Vyazovkin.
This isoconversional technique calculates the activation energy as a function of the degree of the conversion. In this article,
the pyrolysis of cellulose in cotton fibers compared to microcrystalline cellulose (Avicel, PH 105) was investigated. TG curves
were acquired as a function of the heating rates (4, 5, 8, 10, and 16 °C min−1) and the model-free method was used to analyze the data. Activation energies of cotton fibers and Avicel were obtained, and
compared to the data reported in the literature. In addition, models for isothermal decomposition were calculated and compared
with experimental data at the same temperature.
Authors:D. Bhattacharjya, T. Selvamani, and Indrajit Mukhopadhyay
such as the Friedman isoconversion method, Flynn–Wall Method, Kissinger Method are far superior to that obtained by other modelfittingapproach such as the differential method [ 16 , 17 , 24 ]. Thermal decomposition of hydromagnesite has also been
Authors:Dragica M. Minić, Maja T. Šumar-Ristović, Đenana U. Miodragović, Katarina K. Anđelković, and Dejan Poleti
can be applied when the form of the function p ( x ) is known.
When studying kinetics of solid-state reactions two different approaches: “model-fittingapproach” and “model-free approach” are in use.
The model-fittingapproach attempts
Authors:Edjane F. B. Silva, Marcílio P. Ribeiro, Ana C. F. Coriolano, Ana C. R. Melo, Anne G. D. Santos, Valter J. Fernandes Jr., and Antonio S. Araujo
Vyazovkin , S , Wight , CA . Model-free and model-fittingapproaches to kinetic analysis of isothermal and nonisothermal data . Thermochim Acta . 1999 ; 340 : 53 – 68 . 10.1016/S0040-6031(99)00253-1 .
Authors:V. M. Abdul Mujeeb, M. H. Aneesh, K. Muraleedharan, T. G. Devi, and M. P. Kannan
state reactions [ 10 – 12 ].
Thermogravimetry (TG)—isothermal or nonisothermal - has been liberally used to obtain thermal stability parameters of solids [ 13 – 19 ]. It has been reported [ 17 ] that the popular modelfittingapproach gives