Instruments and Techniques
Differential Scanning Calorimeter
Perkin Elmer DSC -7
The Perkin Elmer DSC 7 is connected to a computer via TAC 7/DX Thermal Analysis Instrument Controller. The Pyris Software for Windows installed on the computer controls the DCS 7 via temperature control programs.
The DSC 7 is used for the calorimetric measurement, characterization, and analysis of thermal properties of materials. Using the Pyris Software for Windows, you can program the DSC 7 to run from an initial to a final temperature through transitions in the sample material such as melting, glass transitions, solid state transitions, or crystallization. The temperature range is scanned by changing the temperature at a linear rate in order to study these endothermic and exothermic reactions of samples. The DSC 7 also can be used to gather and analyze date from isothermal reactions such as crystallization or curing.
The differential scanning calorimeter can analyze solid or liquid samples. Solid samples can be in film, powder, crystal, or granular form. Although quantitative accuracy will remain the same regardless of sample shape, the qualitative appearance of run may be affected by the sample configuration. Proper sample preparation that maximizes the contact surface between the pan and the sample will reduce the resistance of the sample to heat flow though the DSC temperature sensors and will result in maximum peak sharpness and resolution. The best sample shapes for optimum performance are thin desks or film or fine granules spread in thin layer on the bottom of the pan. Materials such as polymer films can be conveniently prepared by cutting out sections of the film with a standard paper punch or cork borer. Solid materials can be sliced with a razor or knife.
The DSC 7 can be used to analyze samples from a temperature of 2 ° C to 725° C. Isothermal analyses also can be performed at any selected temperature in the range of the instrument.
Calibration Reference Materials from Ambient to 72 ° C
Very-high-purity metals or inorganic materials are typically used to calibrate the temperature and energy axes of the DSC when operating in the temperature range from ambient to 725° C.
|Reference Material||Transition Point (°C)||Transition Engery (J/g)|
|Potassium Sulfate||485.0 ± 0.5||33.26|
|Potassium Chromate||670.5 ± 0.5||35.56|