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Differential Scanning Calorimetry (DSC) is used to determine a wide range of physical properties of materials, including the glass-transition temperature Tg, the melting temperature Tm, and solid-solid transitions. In this technique, a sample and a reference material are subject to a controlled temperature program. When a phase transition such as melting occurs in the sample, an input of energy is required keep sample and reference at the same temperature. This difference in energy is recorded as a function of temperature to produce the DSC trace.
Modulated DSC provides the same qualitative and quantitative information about physical and chemical changes as conventional DSC, and it also provides unique thermochemical data that are unavailable from conventional DSC. The effects of baseline slope and curvature are reduced, increasing the sensitivity of the system. Overlapping events such as molecular relaxation and glass transitions can be separated. Heat capacity can be measured directly with modulated DSC in a minimum number of experiments.
Both modulated DSC and DSC measure the difference in heat flow to a sample and to an inert reference. The sample and reference cells are identical. However, modulated DSC uses a different heating profile. Whereas DSC measures heat flow as a function of a constant rate of change in temperature, modulated DSC superimpose a sinusoidal temperature modulation on this rate. The sinusoidal change in temperature permits the measurement of heat-capacity effects simultaneously with the kinetic effect. Typical experimental procedure for an initial modulated DSC experiment include a heating rate from isothermal to 5 °C/min and a modulation amplitude from 0.01 to 10 °C. The modulation period can vary from 10 to 100 seconds or, expressed as a frequency, from 10 to 100 MHz.
Please contact Krystyna Brzezinska (kbrzez@mrl.ucsb.edu) to schedule training. Before training starts please read MANUAL.
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