Guidelines When Using the PCA

 

When planning and running experiments using the PCA/DSC system, please review the following additional experimental considerations:

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NOTE:  It is recommended that the Unload Temperature Range parameter (selected on the Post Test Parameters window when you set up your experimental procedure) be set to 35 to 40C.  After prolonged PCA experiments at 50C, the outside of the quartz window on top of the DSC reaches about 17C.  However, at the end of an experiment, in the few minutes it takes for the cell to achieve the recommended 35 to 40C unload temperature, the outer quartz window temperature has increased back to the 24 to 26C range.

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NOTE:  Because the heat capacity signal during PCA light exposure is not valid information, It may be desirable when plotting results to only show the heat capacity before and after exposure as shown in the figure below. This can be accomplished by using the "exclude data" function in Universal Analysis.

Heat Capacity Before and After Exposure

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The MDSC reversing heat flow signal is directly related to heat capacity.  Therefore, measuring the change that occurs in MDSC reversing heat flow as the result of specific PCA exposure conditions, is another option for differentiating similar materials.

Equilibrate at 35C

Data Storage:  ON

Data Collection:  0.1 seconds/data point

Isothermal for 0.5 minute

Modulate + 0.2C every 40 seconds

Isothermal for 1 minute

Modulate + 0C every 40 seconds

Isothermal for 0.5 minute

EVENT:  ON

Isothermal for 2 minutes

EVENT:  OFF

Isothermal for 1 minute

Modulate + 0.2C every 40 seconds

Isothermal for 5 minutes

 

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).

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