29 No. 5
Guidelines for Modulated-Temperature Differential Scanning Calorimetry
A project to establish and propose guidelines and recommendations for using modulated-temperature differential scanning calorimetry has been approved by the International Association of Chemical Thermodynamics to become a project of the Physical and Biophysical Chemistry Division. An international task group (including experts from France, Germany, Japan, Poland, and USA) has been set up to prepare documented recommendations on methods of operation and guidelines on standardized ways of selecting the different parameters of modulation in the use of modulated-temperature differential scanning calorimeters.
Modulated-temperature differential scanning thermal analysis techniques are widely used in many fields. Particularly in pharmaceutical, food, and polymer studies where first order transitions, glass transitions, and polymorphism are key issues. All sorts of relaxation phenomena, as well as coupled thermal and kinetic contributions, can be investigated advantageously and selectively studied with such techniques. Typically, calorimetric measurements are subject to systematic errors, especially when they depend upon the choice of physical parameters such as amplitude and period of modulation and the temperature scanning rate. It is not only the instrument used that is important, but the sample itself that requires the parameters to be tuned to optimize the response of the instrument in order to eliminate systematic errors and get full unambiguous information. It has to be recognized that whatever the instrument and the associated methodology used, the same quantitative information must be obtained on a given sample.
Extension will be made to thermal analysis techniques, where a modulation is superimposed to the temperature ramp, underlying the basic principles and the derived mathematical description of the data treatment. The different methods of measurement and calculation of the main thermodynamic quantities, such as specific heat capacities, first order transitions, and glass transitions, will be carefully analyzed. Clear descriptions will be given of the operating procedures and methodologies for the different typical aspects associated with the techniques. The project should provide a consistent set of internationally accepted recommendations for the use of modulated-temperature calorimetry.
For more information contact Task Group Chairman Jean-Pierre E. Grolier <j-pierre.Grolier@univ-bpclermont.fr>.
last modified 18 September 2007.
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