Dynamic differential scanning calorimetry heat flow measurement

Differential scanning calorimetry (DSC) is a calorimetric method that finds widespread use in many fields, including protein dynamics, polymers, pharmaceuticals, and inorganic materials. DSC measures energy (heat) flow into a sample and a reference substance as a function of controlled increase or decrease of temperature. In a typical power-compensated DSC (Fig. 3.2), the sample and reference are placed on metal pans in identical furnaces each containing a platinum resistance thermometer (thermocouple) and heater. During a thermal transition (e.g., when a physical change in the sample occurs),... 

Besides TMA, two other methods are commonly used to measure Tg. These are differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). DSC measures heat flow versus temperature rather than dimensional changes as measured by TMA. The heat absorbed or given off will change as the temperature increases through the Tg of the resin system.Tg measured by DSC is typically higher than measurements by TMA. DMA measures the modulus of the material versus temperature and also typically results in higher measured values of Tg. 

Temperature-modulated differential scanning calorimetry (T-MDSC) applies a thermal modulation in temperature to a conventional DSC mn and determines a dynamic heat capacity from the relationship between the modulation components of temperature and of heat flow. Primary application of this technique has been the measurement of specific heat capacity and the examination of the anomaly in a relaxation process such as alpha process related to the glass transition. An application to the first-order phase transitions of crystallisation and melting of polymer crystals has recently been suggested. The method and typical results are described. 13 refs. 

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