Question

In: Chemistry

6. What technique(s) would you use to determine crystallinity in a polymer? 7. What thermal instrumental...

6. What technique(s) would you use to determine crystallinity in a polymer?

7. What thermal instrumental technique would you use to determine Tg?

Solutions

Expert Solution

1)I believe the DSC(differential scanning calorimetry) is the most reliable method if executed properly. The melting transition is directly related to the content of polymer crystals, but would be somewhat affected by the heating rate, the contact of the material with the pan and the amount of the polymer in the pan.

2)

The answer depends on many parameters: amount of sample, uniformity of the thin film and area, the need for a substrate... For nanoconfinements it is hard to obtain samples of the order of few grams. Coupled with the poor resolution of DSC (for TG)you should look for something else.

For nice and uniform films, if you can peel them, DMA may be an approach. This depends on the mechanical properties of the film and on DMA limitations. If you cannot remove the polymer from the substrate DMA in compression may not be the best idea. However, you can check it....So, in this case you move to optical methods (interferometry) or reflectivity measurements.


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