Modulated differential scanning calorimetry heat flow measurement

Calorimetric studies have depicted the impact of nanoparticles on isothermal curing of epoxy-amine system. Isothermal measurements done at 298 K using temperature-modulated differential scanning calorimetry are shown in Figure 9.15. The heat flow signal recorded during this measurement is directly proportional to the reaction rate of the curing process. It was foxmd that,... 

The sample (or furnace) temperature is controlled to follow a set course with superimposed periodical changes, and the heat flow rate is measured via the differential temperature between sample and reference (temperature-modulated differential scanning calorimetry, TMDSC [38]). 

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. 

Differential scanning calorimetry (DSC) compares the two different heat flows one to or from the sample to be studied, and the other to or from a substance with no phase transitions in the range to be measured, e.g. glassmaking sand. Figures 1.45.1 and 1.45.2 show artist s views of parts of a modulated DSC system, and Figure 1.46 shows a commercial apparatus for DSC measurements. 

DTA (Differential Thermal Analysis) and DSG (Differential Scanning Calorimetry) measure the thermal transitions in materials by monitoring temperatures and heat flows. DTA is qualitative while DSC is quantitative. Glass transition temperatures, phase changes, heat capacity, cure kinetics and thermal degradation can be monitored by these techniques. Modulated DSC can be both faster and more accurate. 

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