Differential thermal analysis typical curves from

FIGURE 2.6. Typical Curves Obtained from (A) Constant Heating Rate Tests, (B) Isothermal Tests, ( C) Differential Thermal Analysis and (D) Adiabatic Calorimetry... 

Many different test methods can be used to study polymers and their physical changes with temperature. These studies are called thermal analysis. Two important types of thermal analysis are called differential scanning calorimetry (DSC) and differential thermal analysis (DTA). DSC is a technique in which heat flow away from a polymer is measured as a function of temperature or time. In DTA the temperature difference between a reference and a sample is measured as a function of temperature or time. A typical DTA curve easily shows both Tg and T . 

ETA is usually carried out in conjunction with other TA techniques, most notably differential thermal analysis (DTA) and EGA. In this context, ETA can be considered as a coupled TA technique. Carrier gas, at a constant flow rate, is used to carry released gas from the sample to appropriate detectors -usually radioactive counting devices. In the case of desorbed radon, a scintillation counter is used, whereas Geiger counters are used for krypton, xenon, and argon. A typical ETA system is shown schematically in Figure 1. An ETA curve is a plot of emanating power E as a function of time and the E/time relationship has been developed and defined by Balek. 

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