Nonlinear Isoconversional Method Research Articles

Kinetic analysis of complex chemical reactions by coupling model-free and model-fitting analysis

Three different complex multi-step reaction mechanisms of parallel-competing, consecutive and parallel-independent reactions were simulated for two different sets of kinetic parameters. The two sets were chosen in such a way to represent two very different situations. An advanced non-linear isoconversional method (NLN) and a multiple heating rates model-fitting method using nonlinear optimization (NLO) were applied to the data. The errors in kinetic parameters were evaluated for each set of data and for each method. It is shown that analysis of the thermoanalytical curves and of the Eα-dependencies can be used in complementary with the model-fitting approach for the elucidation of the reaction mechanisms and estimation of the kinetic parameters of each step. In most cases, NLO improved the accuracy of the kinetic parameters obtained from NLN method, but only if the mechanism was known. However, selecting the right mechanism is an essential problem of NLO. The study showed that it was possible to accurately fit the mechanism of two consecutive steps with a model of two independent steps that resulted in evaluating invalid kinetic parameters. This example also highlights an important limitation of the so-called deconvolution kinetic analysis which consists in fitting of various multi-step reaction mechanisms with a model of independent steps.

Influence of carbon black filler on pyrolysis kinetic behaviour and TG-FTIR-GC–MS analysis of glass fibre reinforced polymer composites

Recently, several filler materials, such as carbon black (CB), have been added to glass fibre reinforced polymers (GFRP) to enhance their mechanical and electrical performance. So far, we have insufficient information on the effect of these additives on the recyclability of GFRP and the resulting products. Within this context, this is the first research developed to study the effect of these additives on pyrolysis behaviour of GFRP. The experiments were started with dispersion of CB in epoxy resin solution, then CB/GFRP panels were prepared using vacuum-assisted resin transfer technique, followed by grinding to prepare the feedstock. The ultimate, proximate, and morphological properties of the CB/GFRP samples were analysed. Afterwards, TG-FTIR-GC measurements were conducted on the milled samples at several heating rates. Depending on the TG analysis, the pyrolysis kinetics of CB/GFRP were studied using both linear and nonlinear isoconversional methods (i.e., Kissinger, KAS, FWO Friedman, Vyazovkin, and Cai). Also, TGA-DTG data was simulated using the distributed activation energy model and the independent parallel reactions kinetic model. The results show that the fibre is rich in volatile content (45%), while aromatic benzene and C–H bond were the major groups in the TG-FTIR analysis. In addition, phenol and p-Isopropenylphenol were the major compounds in the GC-Ms measurements with abundance of 67% (with improvement of 146% compared with neat GFRP) and 33%. Meanwhile, the pyrolysis kinetic showed that KAS, Vyazovkin, and Cai models are the most appropriate isoconversional methods that can be used to study of the pyrolysis kinetic of CB/GFRP with estimated activation energies in the ranges of 198–209 kJ/mol (with improvement of 64% compared with neat GFRP). Based on that, the filler materials added to GFRP composites, including CB filler, act as self-catalysts during the pyrolysis treatment leading to increased yield and better quality of the formulated volatile compounds.

Pyrolysis Kinetic Behaviour of Glass Fibre-Reinforced Epoxy Resin Composites Using Linear and Nonlinear Isoconversional Methods.

Due to the increasing demand for glass fibre-reinforced epoxy resin composites (GFRC), huge amounts of GFRC waste are produced annually in different sizes and shapes, which may affect its thermal and chemical decomposition using pyrolysis technology. In this context, this research aims to study the effect of mechanical pre-treatment on the pyrolysis behaviour of GFRC and its pyrolysis kinetic. The experiments were started with the fabrication of GFRC panels using the vacuum-assisted resin transfer method followed by crushing the prepared panels using ball milling, thus preparing the milled GFRC with uniform shape and size. The elemental, proximate, and morphology properties of the panels and milled GFRC were studied. The thermal and chemical decomposition of the milled GFRC was studied using thermogravimetric coupled with Fourier-transform infrared spectroscopy (TG-FTIR) at different heating rates. Meanwhile, the volatile products were examined using TG coupled with gas chromatography–mass spectrometry (GC-MS). The TG-FTIR and TG-GC-MS experiments were performed separately. Linear (Kissinger–Akahira–Sunose (KAS), Flynn–Wall–Ozawa (FWO), and Friedman) and nonlinear (Vyazovkin and Cai) isoconversional methods were used to determine the pyrolysis kinetic of the milled GFRC based on thermogravimetry and differential thermal gravimetry (TG/DTG). In addition, the TG/DTG data of the milled GFRC were fitting using the distributed activation energy model and the independent parallel reactions kinetic model. The TG results showed that GFRC can decompose in three stages, and the main decomposition is located in the range 256–500 °C. On the other hand, aromatic benzene and a C-H bond were the major functional groups in the released volatile components in FTIR spectra, while phenol (27%), phenol,4-(1-methylethyl) (40%), and p-isopropenylphenol (34%) were the major compounds in GC-MS analysis. Whereas, the kinetic results showed that both isoconversional methods can be used to determine activation energies, which were estimated 165 KJ/mol (KAS), 193 KJ/mol (FWO), 180 KJ/mol (Friedman), 177 KJ/mol (Vyazovkin), and 174 KJ/mol (Cai).

Determining the Activation Energy of Solid-State Phase Transformation of 1035 Steel from Isoconversional Analysis of DSC Data

The results of solid-state phase transformation kinetics analysis for the steel have been controverted because of the complexity and diversity. In this paper, the activation energy, which represents the energy barrier for austenite to pearlite solid-state phase transformation of 1035 steel, was determined from the nonlinear isoconversional method. The result shown that the activation energy is change with the degree of transformation. Therefore, the nonlinear isoconversional approach maybe a better way to calculate the activation energy of solid-state phase transformation.

Estimating errors in the determination of activation energy by advanced nonlinear isoconversional method applied for thermoanalytical measurements performed under arbitrary temperature programs

In a previous paper (Thermochim. Acta 670 (2018) 1–6) it was shown that the estimation of errors (ΔE) in the determination of apparent activation energies (E) determined by a nonlinear isoconversional method applied for thermoanalytical measurements performed under constant heating rates involves the following successive steps: (1) the determination of Fisher confidence interval (ΔFE) for confidence level of 95 % by applying the procedure suggested by Vyazovkin and Wight, and (2) the application of the relation: ΔE=0.2447×ΔFE+0.00037×ΔFE2. The check of this procedure when using advanced nonlinear incremental isoconversional method (A-NL method) suggested by Vyazovkin is applied for thermoanalytical data under arbitrary temperature programs has been performed for: simulated sinusoidal modulated data, thermogravimetric (TG) data for thermal decomposition of a sort of high density polyethylene (HDPE) under quasi-isothermal conditions, and TG data corresponding to thermal decomposition of a sort of low density polyethylene under arbitrary temperature programs. It has been concluded that the suggested procedure for estimating the error in E evaluation based on above relationship is also applicable when A-NL method is used for kinetic analysis of thermoanalytical data recorded under arbitrary temperature programs.

CINÉTICA E MECANISMO DE OXIDAÇÃO DE UM CONCENTRADO DE ESFALERITA

The oxidation of sphalerite (ZnS) concentrate by gaseous oxygen was carried out by means of thermogravimetric analysis (TGA). The products of oxidation were analyzed by X-ray difractometry and microscopy electronic scanning (MEV/EDS) and the formation of zinc sulphate was detected during the oxidation process. The pyrite present on concentrate was roasted at lower temperature than sphalerite and the mechanism of oxidation was in agreement with the mechanism proposed by Dunn J. G. et. al. (1989). The kinetics of sphalerite oxidation was evaluated by mean of Ozawa-Flynn-Wall (OFW), Kissinger-Akahira-Sunose (KAS) and nonlinear (MNL) isoconversional method and the results suggest that the oxidation process follow a complex mechanism. The values of activation energy founded were higher than 40kJ/mol at full range of conversion and suggest that the controlling step takes place via chemical reaction.

Kinetics of nonisothermal dehydration of unirradiated and γ-ray irradiated neodymium (III) acetate hydrate

Abstract Kinetics of dehydration of unirradiated and γ-ray irradiated neodymium (III) acetate hydrate with 103 kGy total γ-ray dose absorbed in air atmosphere were studied by isoconversional nonisothermal method. The dehydration proceeds in two steps with the elimination of 0.8 and 0.4 mol of H2O, respectively. This result indicates that the investigated neodymium (III) acetate hydrate contains 1.2 mol of crystalline water in its structure. The dehydration reactions are best described by nucleation (A 2 model) and gas diffusion (D 4 model) for unirradiated and γ-ray irradiated samples, respectively. Analysis of the kinetic data using linear and nonlinear isoconversional methods showed that the apparent activation energy, Ea (kJ/mol) is dependent on the conversion degree, α, of the dehydration process. The Ea−α plots for both unirradiated and γ-ray irradiated neodymium (III) acetate hydrate showed that the dehydration is a complex process and contains multistep reactions. The results showed that γ-ray irradiation has a significant effect on the kinetics and thermodynamic parameters of the dehydration reaction. Powder X-ray diffraction showed that neodymium (III) acetate hydrate has a monoclinic system (SG P2/m) and no phase transformation was detected by γ-ray irradiation up to 103 kGy absorbed dose. The system maintains the same crystal structure before and after dehydration.

Estimating errors in the determination of activation energy by nonlinear methods applied for thermoanalytical measurements performed under constant heating rates

Several linear and nonlinear isoconversional methods have been applied for following non-isothermal thermoanalytical data: simulated data for two consecutive first order reactions (12 heating rates), crystallization of (GeS2)0.3(Sb2S3)0.7 (4 heating rates), decomposition of ammonium perchlorate (6 heating rates) and decomposition of poly(vinyl chloride) (PVC) (5 heating rates). It has been considered some pairs “linear isoconversional method + nonlinear isoconversional method”. The “differential pair” is “differential isoconversional method suggested by Friedman + nonlinear differential method”, while each “integral pair” corresponds to a certain approximation of the temperature integral. The values of activation energy (E), error of E obtained by linear method and applying the method of least squares (ΔLE), and Fischer confidence interval obtained for confidence levels of 68.27%, 80%, 90% and 95% by nonlinear method (ΔFE) applying the procedure suggested by Vyazovkin and Wight have been determined for each pair of methods and several conversion degrees. It has been turned out that, for a certain pair of methods, (a) ΔFE values are substantially greater than ΔLE values, and (b) the values of E determined by linear method are identical with those determined by the nonlinear method. The statement (a) is explained by the procedure for ΔFE evaluation in which it is assumed that ΔFE correspond to maximum value of Fischer distribution function. According statement (b) it is expected that is a relationship between ΔLE and ΔFE. Both statements suggest that the error in E determined by a nonlinear isoconversional method is equal with ΔLE. Satisfactory fittings of ΔLE vs. ΔFE have be obtained for the relationships: (1) ΔLE=a×ΔFE and (2)ΔLE=b×ΔFE+c×ΔFE2, here a, b and c are parameters which depend on the confidence limit. These relations have been also checked for high density polyethylene (HDPE) decomposition data that were not used for their derivations. For all considered data, the best accuracy of fitting of ΔLE vs. ΔFE has been obtained for Eq. (2) and ΔFE determined for confidence level of 95%. It has been conclude that the evaluation of error in E determined by a nonlinear isoconversional method involves the following two successive steps: the determination of ΔFE for confidence level of 95%, and the application of relation (2).

Thermal decomposition of un-irradiated and γ-ray irradiated holmium acetate tetrahydrate. Part 1: kinetics of nonisothermal dehydration of un-irradiated and γ-ray irradiated Ho(CH3COO)3⋅4H2O

Abstract Nonisothermal dehydration of un-irradiated and γ-ray irradiated holmium acetate tetrahydrate with 103 kGy total γ-ray dose absorbed was studied in air atmosphere. The thermal decomposition experiments were conducted at heating rates of (5, 7.5 and 10°C/min). The results showed that for un-irradiated material, the dehydration process proceeds in two decomposition steps with the elimination of 3.0 and 1.0 moles of H2O, respectively. The apparent activation energy, E a , as given by both linear and nonlinear isoconversional methods showed dependence upon the conversion degree, α, in the range of 0.2–0.75 for the two dehydration steps. In the first dehydration step, the Ea decreases from 228.0 kJ/mol at the beginning of the decomposition to ≈64.0 kJ/mol at the end of the process. In the second dehydration step, the Ea increases from 42.0 to 72.0 kJ/mol by progressively increasing in α. Compared with solid state reaction models, the two reactions are best described by diffusion (D 4) and nucleation (A 3) models for the first and second dehydration steps, respectively. The results derived from nonisothermal data present a reliable prediction of isothermal kinetics. Straight lines and reduced time plots methods were applied for the determination of the kinetic triplet [Ea , ln A, and reaction model f(α)] from predicted isothermal data. For γ-ray irradiated samples of Ho(CH3COO)3⋅4H2O with 103 kGy total absorbed dose, the dehydration proceeds in two overlapped steps controlled by D 3 model. X-ray data showed phase transformation from monoclinic (SG P2/m) to tetragonal phase (SG P4/mmm) by the elimination of water content from the entire structure of Ho(CH3COO)3⋅4H2O. γ-Ray irradiation effects on the thermal decomposition of Ho(CH3COO)3⋅4H2O were evaluated and discussed based on the formation of trapped electrons, point defects, cation and anion vacancies and cluster imperfections in the host lattice of Ho(CH3COO)3⋅4H2O.

Study of the thermal behavior in solid state of Mn(II)-Diclofenac Complex

The preparation, characterization and thermal behavior of Mn(II)-diclofenac solid-state complex was investigated by simultaneous TG/DTA and DTG curves, DSC, X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) techniques. The thermal evaluation was carried out with sample masses of 2 and 5 mg, with the purpose of comparing the values of activation energy regarding dehydration, monotropic phase transition and thermal decomposition in both samples mass. The DSC curves were obtained in opened and with crimped lids crucibles of aluminum under oxygen purge gas and static air (without purge gas). The DTA and DSC curves show an exothermic peak between 150-180 °C depending on heating rate, which can be attributed to the monotropic non-reversible reaction. The activation energy (Ea/kJ mol-1) to dehydration, the monotropic phase transition and the first thermal decomposition step were determined by Capela-Ribeiro nonlinear isoconversional method. The activation energy under oxygen dynamic purge gas shows lower values compared to those obtained under static air.

Isoconversional approach for non-isothermal decomposition of un-irradiated and photon-irradiated 5-fluorouracil

Kinetic analysis for the non-isothermal decomposition of un-irradiated and photon-beam-irradiated 5-fluorouracil (5-FU) as anti-cancer drug, was carried out in static air. Thermal decomposition of 5-FU proceeds in two steps. One minor step in the temperature range of (270–283°C) followed by the major step in the temperature range of (285–360°C). The non-isothermal data for un-irradiated and photon-irradiated 5-FU were analyzed using linear (Tang) and non-linear (Vyazovkin) isoconversional methods. The results of the application of these free models on the present kinetic data showed quite a dependence of the activation energy on the extent of conversion. For un-irradiated 5-FU, the non-isothermal data analysis indicates that the decomposition is generally described by A3 and A4 modeles for the minor and major decomposition steps, respectively. For a photon-irradiated sample of 5-FU with total absorbed dose of 10Gy, the decomposition is controlled by A2 model throughout the coversion range. The activation energies calculated in case of photon-irradiated 5-FU were found to be lower compared to the values obtained from the thermal decomposition of the un-irradiated sample probably due to the formation of additional nucleation sites created by a photon-irradiation.The decomposition path was investigated by intrinsic reaction coordinate (IRC) at the B3LYP/6-311++G(d,p) level of DFT. Two transition states were involved in the process by homolytic rupture of NH bond and ring secession, respectively.

Crystallization kinetics of Ti20Zr20Cu60 metallic glass by isoconversional methods using modulated differential scanning calorimetry

The study of crystallization kinetics of amorphous alloys has been a matter of great interest for material researchers for past few decades, since it provides information about the kinetic parameters i.e., activation energy of crystallization and the frequency factor. These kinetic parameters can be calculated by model-free isoconversional methods. Isoconversional methods allow calculating the activation energy as a function of degree of conversion, α. Hence, these methods provide accurate results for multistep processes like crystallization. Model-free methods are categorized as linear and non-linear isoconversional methods. Linear methods are further classified as linear differential and linear integral isoconversional methods. In present work, we have used these isoconversional methods to study the effect of non-linear heating rate, employed by modulated differential scanning calorimetry (MDSC), on the non-isothermal crystallization kinetics of Ti20Zr20Cu60 metallic glass. For Ti20Zr20Cu60, MDSC curves clearly indicate a two-step crystallization process. Both crystallization peaks were studied based on the modified expressions for isoconversional methods by non-linear heating rate. The term corresponding to non-linearity comes out to be (A T ω/2β)2. The effect of non-linear heating rate on measurement of kinetic parameters by isoconversional methods is studied. The activation energy of crystallization is calculated for Ti20Zr20Cu60 metallic glass for various degrees of conversion by linear integral isoconversional methods i.e., Ozawa–Flynn–Wall, Kissinger–Akahira–Sunose, and also with Friedman method which is a linear differential isoconversional method.

The validity of nonlinear isoconversional method in the kinetic analysis of calcium carbonate decomposition under isothermal and non-isothermal conditions

• The nonlinear isoconversional method was applied to determine the kinetics parameter. • The activation energy determined by this method varies with the extent of reaction. • The dependence of the activation energy can excellently predict the actual measurement. • It is demonstrated that this method is a trustworthy way for kinetics analysis. The nonlinear isoconversional method has been applied to data for non-isothermal thermal decomposition of calcium carbonate. The activation energy determined by this method is dependent on the extent of reaction. The dependence of the activation energy has been used to predict the isothermal kinetics. It is shown that the dependence derived from non-isothermal data permits reliable predictions of the isothermal kinetics. Therefore, the nonlinear isoconversional method is recommended as a trustworthy way of obtaining consistent kinetic information from isothermal and non-isothermal.

Determined the Activation Energy of the Decomposition of Calcium Carbonate by Nonlinear Isoconversional Method

The nonlinear isoconversional method has been applied to data for nonisothermal thermal decomposition of calcium carbonate. It is shown that the dependence derived from nonisothermal data can reveal the complexity of solid reaction. Therefore, the nonlinear isoconversional method is recommended as a trustworthy way of obtaining the activation energy of solid reaction under nonisothermal conditions.

Kinetic parameters for thermal decomposition of hydrazine

The propulsion of most of the operating satellites comprises monopropellant (hydrazine––N2H4) or bipropellant (monometilydrazine—MMH and nitrogen tetroxide) chemical systems. When some sample of the propellant tested fails, the entire sample lot shall be rejected, and this action has turned into a health problem due to the high toxicity of N2H4. Thus, it is interesting to know hydrazine thermal behavior in several storage conditions. The kinetic parameters for thermal decomposition of hydrazine in oxygen and nitrogen atmospheres were determined by Capela–Ribeiro nonlinear isoconversional method. From TG data at heating rates of 5, 10, and 20 °C min−1, kinetic parameters could be determined in nitrogen (E = 47.3 ± 3.1 kJ mol−1, lnA = 14.2 ± 0.9 and Tb = 69 °C) and oxygen (E = 64.9 ± 8.6 kJ mol−1, lnA = 20.7 ± 3.1 and Tb = 75 °C) atmospheres. It was not possible to identify a specific kinetic model for hydrazine thermal decomposition due to high heterogeneity in reaction; however, experimental f(α)g(α) master-plot curves were closed to F1/3 model.

Kinetic parameters for thermal decomposition of supramolecular polymers derived from diclofenac–meglumine supramolecular adducts

Meglumine is an aminocarbohydrate able to form supramolecular adducts with organic acids. The recognition is based on hydrogen bonds and the structures resulting from the complexation have high solubility in water. This property has been exploited by the pharmaceutical industry in the improvement of existing drugs, and the successful example of this approach involves the poorly soluble non-steroidal anti-inflammatory drugs (NSAIDs). Investigation of the thermal behavior of adduct obtained from meglumine and the NSAID diclofenac revealed that a polymer-like material is formed from the self-assembly of diclofenac–meglumine adducts in the melt. This polymer showed a high molecular weight around 2.0×105kDa. The kinetic parameters for the thermal decomposition step of the polymer were determined by the Capela–Ribeiro non-linear isoconversional method. From data for the TG curves in nitrogen atmosphere and heating rates of 5, 10, 15 and 20°Cmin−1, the Eα and Bα terms could be determined, and consequently the pre-exponential factor, Aα, as well as the kinetic model, g(α).

Thermal stability of habit modified ammonium nitrate: Insights from isoconversional kinetic analysis

Compared to the conventional ammonium perchlorate based solid propellants, burning of ammonium nitrate (AN) based propellants produce environmentally innocuous combustion gases. However, the near room temperature phase transition limits the application of AN as a propellant ingredient. A method to produce phase modified ammonium nitrate (PMAN) was reported by means of habit modification route using potassium ferrocyanide. In the present study, the thermal stability and moisture absorption characteristics of PMAN were evaluated to understand the viability of its application in the environmentally benign propellant systems. The energy of activation of decomposition reaction of AN, PMAN and an admixture of AN-potassium ferrocyanide trihydrate were computed by Friedman's differential and Vyazovkin's non-linear integral isoconversional methods and used to ascertain their thermal stability. The moisture absorption characteristics were determined at 53 and 62% RH and the cyclic DSC analysis, combination of non-isothermal and isothermal, was used to trace the phase behaviour of the PMAN. The study indicates that PMAN and AN has comparable properties suggesting similar processing and handling conditions.

Kinetic parameters for thermal decomposition of supramolecular polymers derived from flunixin-meglumine adducts

Meglumine, (2R,3R,4R,5S)-6-methylaminohexane-1,2,3,4,5-pentol, is a carbohydrate derived from sorbitol in which the hydroxyl group in position one is replaced by a methylamine group. It forms binary adducts with substances having carboxyl groups, which have in common the presence of hydrogen bonding as the main force in the stabilization of these species. During melting, adducts of meglumine with flunixin (2-[[2-methyl-3-(trifluoromethyl)phenyl]amino]pyridine-3-carboxylic acid) polymerize or self-assemble in amorphous supramolecular structures with molecular weights around 2.0 × 105 kDa. DSC curves, in a first heating, show isomorphic transitions where the last one at 137 °C for the flunixin-meglumine adduct originated the supramolecular amorphous polymers with glass transition around 49.5 °C. The kinetic parameters for the thermal decomposition step of the polymers were determined by the Capela-Ribeiro non-linear isoconversional method. From data for the TG curves in nitrogen atmosphere and heating rates of 5, 10, 15, and 20 °C min−1, the E α and B α terms could be determined and, consequently, the pre-exponential factor, Aα, as well as the kinetic model, g(α).

Kinetic parameters for thermal decomposition of microcrystalline, vegetal, and bacterial cellulose

Cellulose can be obtained from innumerable sources such as cotton, trees, sugar cane bagasse, wood, bacteria, and others. The bacterial cellulose (BC) produced by the Gram-negative acetic-acid bacterium Acetobacter xylinum has several unique properties. This BC is produced as highly hydrated membranes free of lignin and hemicelluloses and has a higher molecular weight and higher crystallinity. Here, the thermal behavior of BC, was compared with those of microcrystalline (MMC) and vegetal cellulose (VC). The kinetic parameters for the thermal decomposition step of the celluloses were determined by the Capela-Ribeiro non-linear isoconversional method. From data for the TG curves in nitrogen atmosphere and at heating rates of 5, 10, and 20 °C/min, the Eα and Bα terms could be determined and consequently the pre-exponential factor Aα as well as the kinetic model g(α). The pyrolysis of celluloses followed kinetic model \( g(\alpha ) = [ - \ln (1 - \alpha )]^{{{1 \mathord{\left/ {\vphantom {1 {1.63}}} \right. \kern-\nulldelimiterspace} {1.63}}}} \) on average, characteristic for Avrami–Erofeev with only small differences in activation energy. The fractional value of n may be related to diffusion-controlled growth, or may arise from the distributions of sizes or shapes of the reactant particles.

Kinetics of Crystallization of Co-Based Multi-Component Amorphous Alloy

Abstract Crystallization is a thermally activated process in non-crystalline and amorphous solids. The kinetics of the solid state phase transformations can be studied using thermal analysis techniques such as differential scanning calorimetry (DSC). For the kinetic analysis of the crystallization process under non-isothermal conditions, the choice of a reliable method is very important. The methods for the analysis of non-isothermal data are, in general, derived by extending the formalism developed for isothermal conditions. Most methods for the kinetic analysis of crystallization processes rely on the isokinetic hypothesis to separate the kinetics of the transformation from its dependence on temperature. It is assumed that the transformation rate can be described by a differential equation separable in α (transformed fraction) and T (temperature), i.e., for continuous heating regime, (dα/dT)=(1/β)k(T)f(α), where β is the heating rate, k(T) is the rate constant, and f(α) is the kinetic function (reaction model). The crystallization kinetics of glassy Co66Si16B12Fe4Mo2 have been studied with DSC and analyzed using non-isothermal theoretical expressions. The Avrami exponent, (n), frequency factor, (A), and activation energy, (E), of crystallization are evaluated using Matusita and Sakka (MS) and modified Kissinger equations. Besides, isoconversional kinetic analysis has been applied to DSC data for the determination of these different kinetic parameters. The isoconversional methods calculate Eα values at progressive degrees of conversion, α, without modelistic assumptions, and hence, this approach takes care of the variation of kinetic parameters with the fraction crystallized. The activation energy has been determined using both linear integral and differential isoconversional methods and also by the non-linear isoconversional method suggested by Vyazovkin and Wight. These methods are found to give consistent results for E. Furthermore, a comparison has been made among various kinetic parameters obtained using different approaches to investigate the relative applicability and usefulness of the proposed methods.