Attached is a typical graph generated by the TGA analyzer. It is known that the degassed temperature for a solid sample can be determined by identifying a point known as the "melting" point of the solid material.
Now, referring to the attached graph, the question is: How can one determine the degassed temperature by obtaining the "melting" point of the solid material from the TGA graph? Which point is it? Point A? Point B? or Point C?
Your feedback will be highly appreciated. Thank you very much.
Photo Source: Qubeissi, M. A. , & El-kharouf, A. , & Soyhan, H. S. , (Eds.). (2020). Renewable Energy - Resources, Challenges, and Applications. IntechOpen. https://doi.org/10.5772/intechopen.81765
Hi,
TGA is inherently insensitive to melting, so there is no general answer to your question. It could only be resolved with additional knowledge of your experimental system and its behavior, but even then, it will not be very accurate. Process 0-A represents the evaporation of volatile content (humidity, residual monomers, organic solvents, etc.), A-B is the primary decomposition, B-C is the secondary decomposition, and C is the residual weight. The volatiles goes away even from solid samples (aka "drying"), but, indeed, the rate is usually faster in liquids due to faster diffusion. However, the rate change could be caused by other means, for instance, by the evaporation of heavier molecules at higher temperatures. Some materials decompose sooner than they melt, so you cannot even say that the melting point is always in this region. Instead of wild guessing, I suggest using a standard method for melting determination, such as DSC.
You can refere to this researchgate discussion
https://www.researchgate.net/post/Can_anyone_explain_how_to_determine_degassing_temperature_for_the_preparation_of_a_material_for_BET_analysis
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