Endothermic process calibration

A heat flow calorimeter and the drop calorimetric method were used by Connor, Skinner, and Virmani to investigate the thermal decomposition of Cr(CO)6 at 514 K (the calibration was made with iodine as described above) [164], The only peak observed corresponded to an endothermic process ... 

Differential Scanning Calorimetry. A Perkin-Elmer Model DSC-IB calorimeter was used to examine crystallinity by measuring areas under the fusion curve as a function of elastomer composition and processing variables. Areas of endotherms were calibrated against an indium standard and the crystallinity calculated using a value of —138 J/g for a 100% crystalline polypropylene polymer (II). 

Manufacturers use two methods of measurements. In the first method called heat flux DSC, the instrument measures this temperature difference (DTA). Through calibration, this temperature difference is transformed into a heat flow, dq/dt. Therefore, there is a thermal factor that may vary with temperature. In the second method, called power compensation DSC, two individual heaters are used in order to monitor the individual heating rates of the two individual ovens. A system controls the temperature difference between sample and reference. If any temperature difference is detected, the individual heatings are corrected in such a way that the temperature is kept the same in both pans. That is, when an endothermic or exothermic process occurs, the instrument delivers the compensation energy in order to maintain equal temperature in both pans. 

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