DSC can be applied to find out the activation energy of any phase transition in materials. According to the Kissinger equation:

ln〖(T^2/β)〗 =(E_A/RT)+A

Where T is the temperature of transition, β is the heating rate (dT/dt = β), E_A is the activation energy, R is the gas constant (8.314 J/mol K), and A is a constant. E_A/R can be obtained from the slope of the plot of ln(T^2/ β) versus (1/T) for different heating rates. Calculated activation energy is a clue to characterize the kinetic of any transition.

It is possible and a normal feature of a tga. Many people using this method to know degradation pattern of chemical at fix temp. Over the period of time. I have used this method several time. Here in this method we have to set temp. First and than put the sample so sample putting time should be minimum in sample pan. Recomended instrument is a horizontal type of tga like perkin elmer's new DTG.

Thank you Mr Purohit.

You may want to try the ASTM E1641 using TGA. I've used it on different samples and atmospheres during my thesis, results are great. Good luck!!

Victor, Vivek -- would you please share any relevant literature that you have published or recommend on this? Thanks.

what kinetic data do you want to measure??

I've measured E, Z, dS, dH with DTA,

If that what you want, I think i can help you.

Dear Palash: I have all of the data, nevertheless I've procastinated on the paper publication. ASTM E1641 is recommended anyway.

DSC can be applied to find out the activation energy of any phase transition in materials. According to the Kissinger equation:

ln〖(T^2/β)〗 =(E_A/RT)+A

Where T is the temperature of transition, β is the heating rate (dT/dt = β), E_A is the activation energy, R is the gas constant (8.314 J/mol K), and A is a constant. E_A/R can be obtained from the slope of the plot of ln(T^2/ β) versus (1/T) for different heating rates. Calculated activation energy is a clue to characterize the kinetic of any transition.

Hi Julio, I think DSC could be a good option, you could start doing a review to the Kissinger Method.

And regarding to your question about isothermal analysis, normally DTA and DSC has capacity to perform these type experiments.

Just need to be careful with the sample preparation.

I thank for all. I want to measure kinetic constants for thermal degradation of tablets and estimate the lifetime using Arrhenius equation or Eyring–Polanyi equation. I read the suggestions. ASTM E1641 and kissinger method are good literatures for obtaining information. Does someone have ASTM E1641 in digital format? Articles describing the Kissinger method was easy to find. Thank you again.

Hi Julio, Hope the attached paper helps to shed some light on the calculation of the kinetic constants.

Thank you Mr Goonoo.

Hi Julio, for a detailed description of transformation kinetics you may check "Analysis of the kinetics of phase transformations", E.J. Mittemeijer, J. of Material science, 1992.

Thank you Mr Villa.

Dear Julio: Please send me an e-mail.

Dear Julio

There is a software, you can calculate the activation energy in a just a few seconds, it's called AKTS (Advanced Kinetic and Technology Solution) all what you need is to load your different heating rates TGA or  DSC curves ( heating rates should be below 8 K/min i.e. 1, 2, 4, 6 ,8 K/min)

http://www.akts.com/

However, if you still interesting in calculating the Ea using Excel, please let me know

Hope this helping

Have a very good day

Ahmed 

Dear Mr. Osman, thank you very much. I'm going to see the software from AKTS. In relation to use Excel sheet, I already made the functions to calculate the kinetic data from TGA. Kind regards.

Dear Julio

You are very welcome

Activation energy is just one of the parameters determining the reaction rate, the other one is the preexponential factor. Both parameters are equally important. The source program treating the data in this sense can be found as a supplementary material to the paper Journal Comp. Chem 36 (2015) 392-398.

Kinetic analysis is for sure never done "in just a few seconds". The AKTS software is suitable but needs a lot of time to learn how to use in a correct manner. The Kissinger equation is only one of different possible models. For details see e.g. chapter 6.3 in our book on DSC, or the attached paper for TGA measurements. Good luck!

Dear G. W. H. Höhne,

Thanks for your answer. The AKTS company offers a training onsite to train the software, after the training, I found it very easy to use the software in order to calculate the kinetic parameters.

Many thanks

Dear Amin For a constant temperature system, you may use hot air oven, if temperature req is less than 250 and a furnace above 250 C, Set the temp and measure the weight loss manually till you  get a constant weight(at an interval of 15 minutes).This is a bit laborious but it works. I have found the decomposition  mmechanis of my compounds this way and confirmed it with its TGA curve.

 DSC can be applied to find out the activation energy of any phase transition in materials. According to the Kissinger equation:

ln〖(T^2/β)〗 =(E_A/RT)+A

Where T is the temperature of transition, β is the heating rate (dT/dt = β), E_A is the activation energy, R is the gas constant (8.314 J/mol K), and A is a constant. E_A/R can be obtained from the slope of the plot of ln(T^2/ β) versus (1/T) for different heating rates. Calculated activation energy is a clue to characterize the kinetic of any transition.

How do I measure kinetic data using TGA or DSC?. Available from: https://www.researchgate.net/post/How_do_I_measure_kinetic_data_using_TGA_or_DSC [accessed Aug 22, 2017].

it is possible and there are many methods in dynamic and isothermal degradation:

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UsingTGA/DTG method you can use the AKTS software to calculate the well know kinetic triplet ( E.A and Alpha) but it is possible to use the origine softWare.

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