TG/DTG/DTA data used for determining the kinetic parameters of the thermal degradation process of an immunosuppressive agent: mycophenolate mofetil

Pătruţescu, Cristina; Vlase, Gabriela; Turcuş, Violeta; Ardelean, Dorina; Albu, Paul

doi:10.1007/s10973-015-4620-2

Cited by 30 publications

(8 citation statements)

References 17 publications

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“…There are currently several mathematical models to evaluate kinetics parameters of thermal degradation data extracted from the TGA analysis of polymers [ 6 , 22 , 39 , 40 , 41 , 42 , 43 , 44 ]. Among them, one of the most successful is the isoconversional integral method of Ozawa-Flynn-Wall, known as OFW [ 22 , 23 , 24 , 26 , 27 , 28 , 29 ]. This model is a free-kinetics model since it considers that the rate constant of the degradation process at a constant degree of conversion ( α ) depends only on the temperature, i.e., the model-free does not depend on the reaction model, f ( α ) [ 39 , 40 , 41 , 45 ].…”

Section: Methodsmentioning

confidence: 99%

“…It has been discussed that an advantageous manner to supervise changes in materials performance due to the action of aging processes is the use of thermal methods, e.g., TGA (thermogravimetric analysis), DSC (differential scanning calorimetry) and DMTA (dynamic mechanical thermal analysis) [ 4 , 7 , 15 ]. Among these methods, DMTA is very suitable for long-term mechanical behavior evaluation [ 7 ], while TGA and DSC are appropriately applied to perform kinetics studies and thermal lifetime estimation [ 6 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ].…”

Section: Introductionmentioning

confidence: 99%

“…In this scope, the application of TGA with multiple heating rates to evaluate polymer's degradation kinetics, as well as to estimate operating lifetime, is a particularly robust and useful thermal methodology that has been widely used [ 6 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]. Among the materials that can be evaluated are polymers and biopolymers, composites, and other organic materials that decompose in first-order kinetics [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]. For those others that do not, the main stage of decomposition can be treated as a first-order kinetics process with good approximation.…”

Section: Introductionmentioning

confidence: 99%

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Kinetics of thermal degradation and lifetime study of poly(vinylidene fluoride) (PVDF) subjected to bioethanol fuel accelerated aging

Silva

Contreras

Nascimento

et al. 2020

Heliyon

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PVDF was prepared by compression molding, and its phase content/structure was assessed by WAXD, DSC, and FTIR-ATR spectroscopy. Next, PVDF samples were aged in bioethanol fuel at 60 °C or annealed in the same temperature by 30 ─ 180 days. Then, the influence of aging/annealing on thermal stability, thermal degradation kinetics, and lifetime of the PVDF was investigated by thermogravimetric analysis (TGA/DTG), as well as the structure was again examined. The crystallinity of ~41% (from WAXD) or ~49% (from DSC) were identified for unaged PVDF, without significant changes after aging or annealing. This PVDF presented not only one phase, but a mixture of α -, β - and γ -phases, α - and β -phases with more highlighted vibrational bands. Thermal degradation kinetics was evaluated using the non-isothermal Ozawa–Flynn–Wall method. The activation energy ( E a ) of thermal degradation was calculated for conversion levels of α = 5 ─ 50% at constant heating rates (5, 10, 20, and 40 °C min ─1 ), α = 10% was fixed for lifetime estimation. The results indicated that temperature alone does not affect the material, but its combination with bioethanol reduced the onset temperature and E a of primary thermal degradation. Additionally, the material lifetime decreased until about five decades ( T f = 25 °C and 90 days of exposition) due to the fluid effect after aging.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Kinetics of thermal degradation and lifetime study of poly(vinylidene fluoride) (PVDF) subjected to bioethanol fuel accelerated aging

Silva

Contreras

Nascimento

et al. 2020

Heliyon

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“…Thermogravimetric (TG) analysis is a common method for obtaining conversion data from the thermal solid‐state reactions, which result in the change of sample mass upon heating under isothermal or nonisothermal conditions . Nonisothermal thermogravimetry with a linear heating rate is the most frequently used technique for thermal analysis of materials .…”

Section: Introductionmentioning

confidence: 99%

Kinetic Analysis of Nonisothermal Decomposition of Acetyl Ferrocene

Das

Bhattacharjee

2018

Int J of Chemical Kinetics

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The work deals with thermal decomposition of acetyl ferrocene in nitrogen atmosphere based on nonisothermal thermogravimetry. It presents a mathematical analysis of nonisothermal thermogravimetric data using multiheating rates to estimate reaction kinetic parameters. Model free (integral isoconversional) methods are employed to analyze the thermogravimetric data. The decomposition is a multistep process. The activation energy Eα of decomposition is conversion (α) dependent. The average values of activation energy are Eα = 49.87, 106.28, and 183.35 kJ mol−1 for three major steps of decomposition. The most probable reaction mechanism function, g(α), for thermal reactions has been identified by the master plot method, and the stepwise reaction mechanisms are found to be different for different steps. The estimated values of the activation energy Eα and g(α) have been utilized in the determination of the reaction rate Aα of thermal decomposition. The α‐dependent reaction rate values are determined and are found to lie in the range of 5.2 × 105 to 3.2 × 104 min−1, 1.7 × 1015 to 7.8 × 106 min−1, and 3.8 × 108 to 1.4 × 107 min−1 for three different steps. Based on the values of Eα, g(α), and Aα, the thermodynamic triplets (ΔS, ΔH, ΔG) associated with the decomposition reactions have been estimated. Estimated kinetic parameters have been used to construct the conversion curves, and those have been successfully compared with the experimentally observed ones.

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“…Thermal methods of analysis have been widely used in the pharmaceutical and food areas to detect the thermal stability [11], evaluation of the thermal decomposition kinetics [12], and gaseous products of the thermal decomposition [13], solid-state reactions [14], and as one of the main methods in the detection of polymorphic forms [6].…”

Section: Introductionmentioning

confidence: 99%

Polymorphism in propyl gallate recrystallized with acetone

Gálico

Nova

Bannach

2016

J Therm Anal Calorim

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A new polymorphic form of the synthetic antioxidant propyl gallate was obtained by the recrystallization of the compound in acetone. The new form was characterized by thermogravimetry, differential scanning calorimetry, X-ray powder diffractometry, and near-and middle-infrared region spectroscopy. While the commercial form of propyl gallate starts to melt at 145°C with the maximum temperature of the peak at 150°C, the recrystallized form starts to melt at 140°C with the maximum temperature of the peak at 148.8°C. The two forms differ much in the X-ray powder diffractograms pattern, confirming the change in the longdistance interactions in both forms but the near-and middleinfrared region spectroscopy shows that no difference occurs in the inter-and intramolecular interactions.

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TG/DTG/DTA data used for determining the kinetic parameters of the thermal degradation process of an immunosuppressive agent: mycophenolate mofetil

Cited by 30 publications

References 17 publications

Kinetics of thermal degradation and lifetime study of poly(vinylidene fluoride) (PVDF) subjected to bioethanol fuel accelerated aging

Kinetics of thermal degradation and lifetime study of poly(vinylidene fluoride) (PVDF) subjected to bioethanol fuel accelerated aging

Kinetic Analysis of Nonisothermal Decomposition of Acetyl Ferrocene

Polymorphism in propyl gallate recrystallized with acetone

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