Differential Scanning Calorimeter (DSC) experiments measure heat flow into or out of a material as a function of temperature and/or time. It can be used to evaluate exothermic or endothermic events that occur in the temperature range from -180 to 725°C. Therefore, DSC is a valuable analytical technique for polymers, organic chemicals, pharmaceuticals, oils and greases, foods and biological materials, as well as metals and some inorganic materials. Typic measurements include:
Glass transitions, crystallization, and melting transitions
Curing reactions and kinetics of thermosets
Oxidative stability of lubricants and polymers
Purity of pharmaceuticals and organics
Specific heat capacity of materials
The DSC can be used to analyze virtually any material that can be put into a DSC sample pan. This includes:
When making quantitative measurements or verifying reproducibility, it is important to ensure good thermal contact between the sample and sample pan. The physical characteristics of the sample affect the quality of this contact.
When using powdered or granular samples, spread them evenly across the bottom of the pan to minimize thermal gradients. For solid samples, select the side of your sample with the flattest surface for contact with the pan. After encapsulating the sample, ensure that the pan bottom is flat. If it is not, flatten it by pressing the pan bottom on a flat surface.
NOTE: The contact between the pan and the raised sample platform is as important as the contact between the sample and sample pan.
NOTE: The oils on your fingers can affect the results of thermal analysis experiments. Always use tweezers when handling sample pans and sample material.
If you overfill a pan, the heating or cooling procedures may cause the sample to boil out, buckle, or explode the pan. If you are using an Autosampler and this occurs so that the Autosampler cannot remove a pan from the cell because of deformation or boiled-out material, operation is halted until the problem is corrected. Therefore, you should be reasonably familiar with the effects of heating and cooling procedures on your samples and pans.
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