ABSTRACT
Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) are commonly used methods to investigate the thermal stability, compositional analysis, and degradation kinetics of multicomponent polymers. TGA measures mass flow into (weight gain) or out of a sample (weight loss) in a controlled atmosphere. The plot of “weight loss vs. temperature” or “weight loss vs. time” provides information such as thermal stability and composition of the original sample, intermediate compounds, and residues remaining after thermal decomposition. Generally, TGA provides information in step-like curve, and thus in complex systems, the overlapping of degradation curves normally occurs. In such cases, overlapping reactions may be well-resolved by plotting the derivative thermogravimetry (DTG) curve, in which the mass change with respect to temperature (dm/dT) is plotted against temperature or time to determine the inflection points which are useful for resolving the complex segments. A peak in the DTG curve occurs when the rate of mass change is a maximum and is characterized by the peak maximum and peak onset temperatures. The area under the DTG curve is proportional to the mass change, and the height of the peak at any temperature gives the rate of mass change at that temperature. In view of the visual similarity between them, DTG curves are frequently referred along with DTA curves (Hatakeyama and Quinn 1999).
