Thermogravimetric analysis fundamentals

Discuss, the fundamental theory of thermogravimetric analysis , and its instrumentation aspects in an elaborated manner. 

By definition [26,27], thermogravimetric analysis is a technique in which the mass of a substance is measured as a function of time or temperature while the substance is subjected to a controlled temperature program. Because mass is a fundamental attribute of a material, any mass change is more likely to be associated with a chemical change, which may, in turn, reflect a compositional change. 

The fundamental research work was subvided into 3 parts [ 6o ] - thermogravimetric analysis (TGA) and differential thermal analysis (PTA) of minute samples (5 50 mg) of the material to be studied. Both techniques yield information on the rate of thermal decomposition, the heat of reaction, the kinetic parameters of this process (pseudo-order and activation energy) and the amount of residue. The analysis of the evolving product has been monitored by means of gas chromatography. High temperature oxidation of the residue allows to compare the reactivity of the carbonized residue. ... 

Figure 10.19 Thermogravimetric curves that exhibit decomposition starting temperature 7) and finish temperature 2. (Reproduced with permission from T. Hatakeyama and F.X. Quinn, Thermal Analysis Fundamentals and Applications to Polymer Science, 2nd ed., John Wiley Sons Ltd, Chichester. 1999 John Wiley Sons Ltd.)...

The other posibility for characterizing structural properties of inorganic sorbents deals with the thermogravimetric analysis. By means of this analysis the pore size distribution, pore volume and specific surface area of adsorbents and catalysts which are fundamental adsorption characteristics may be obtained. 

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