The actual complex temperature/time profile in Modulated DSC® depends on three variables—underlying heating/cooling rate, modulation period, and modulation temperature amplitude. In conventional MDSC experiments, all three variables are operator-selected for best results and the material is evaluated during heating over a temperature range.
If you want to set up a conventional MDSC procedure, you can choose one of two techniques—the DSC Wizard or the Experimental View - Procedure Page. See the instructions below for each technique.
As in conventional DSC experiments, MDSC experiments provide valid information only if the material being evaluated is able to follow the temperature profile generated by the instrument.
When you perform a Conventional MDSC experiment, the following test parameters need to be specified:
Start Temperature & Final Temperature: The starting and final temperatures should be set to cover a wide enough temperature range to observe all the events of interest. As in conventional DSC, the maximum range is -180 to 725°C, but may be reduced depending on the type of sample pan and cooling accessory used.
Ramp Rate: Select an underlying heating/cooling rate of 1 to 5°C/minute. Make sure that the rate chosen provides at least 4 complete temperature modulations (oscillations) over the temperature range of each transition studied.
Modulation Period: Select a modulation period of 20 to 200 seconds. For most materials in crimped pans, 40 to 60 seconds is recommended.
Modulation Temperature Amplitude: Select a temperature amplitude of modulation between ±0.2 and 2.0°C. Larger amplitudes (±1.5 to 2.0°C) should be used when measuring weak transitions. Smaller amplitudes should be used for analysis of sharper transitions which are only a few °C wide. NOTE: Amplitudes below ±0.1°C are not recommended.
Additional Conditions: There are additional experimental conditions that can be changed to optimize specific situations. These are accessed using Advanced Parameters and Post-Test Conditions. For most experiments, the system default values shown are recommended.
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Modulated DSC® and MDSC® are registered trademarks of TA Instruments—Waters LLC.
Modulated DSC® and MDSC® are terms which describe proprietary technology invented by Dr. Mike Reading of ICI Paints (Slough UK) and patented by TA Instruments—Waters LLC (U.S. Patent Nos. B1 5,224,775; 5,248,199; 5,335,993; 5,346,306).
Enter the desired parameters, then select Next to proceed.
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Display the Procedure Page. Select the desired experiment from the list of available preprogrammed templates.
Enter the desired parameters. When you have finished setting up this procedure, you can enter more information by selecting the Notes Page and Summary Page for this run.
Click the Apply button when finished to save these changes or the Append button to save the changes to this run and add another run to the end of the sequence.
NOTE: You can use any test template as the basis for a custom test by selecting the desired test template from the list of tests, then click the Apply button and change the test to Custom. Then you can click on the Procedure Page and then the Editor button to make the changes desired.
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