Question

Exo and endothermic curve in thermogravimetry analysis

Answer 1

It can happen that both an exothermic and endothermic process occur at the same time, for instance when an exothermic cure reaction is accompanied by an endothermic vaporization of water. The DSC curve then consists of the sum of two opposite curves of unknown magnitude, which is impossible to resolve without additional information. In principle, it might be possible it use the TGA data to correct for this, but I've never seen software that does this automatically. In practice, it is more common to suppress the vaporization by running the DSC under pressure.



There are no endothermic/exothermic processes in thermogravimetric analysis. Only weight loss (or possible weight gain) with either changes in temperature ot time.
In DSC, there can be both endo and exothermic events in a single run. For some polymers, a cold crystallization (exothermic reaction) can take place followed by a crystalline melt (endothermic reaction) in a heating run from lower to higher temperatures. The cold crystallization can take place because the sample had been rapidly cooled and is frozen into a non-equilibrium state. As the polymer is heated its molecules can move and crystallize - the equilibrium state.

Answer 2

Answer:

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