Index
Differential
Scanning Calorimetry (DSC)
Materials & Equipment
Sample press (GRBrown E207)
Analytical balance
Sample pans and lids
Tweezers
DSC (GRBrown E204)
PLLA, PLGA
Safety
1. Wear disposable latex gloves at all times
2. Wear safety glasses at all times.
Sample Preparation
NOTE: Sample preparation should be done with GRBrown E207 under the direct supervision of a T.A.
1. Weigh the sample pan and lid. Use tweezers to move and manipulate pan and lid.
2. Place 5-10 mg of PLLA in the pan. Do not allow the sample to spill onto the lip of the pan.
3. Place the lid on the pan. Be careful to center the lid on the pan.
4. Using tweezers, place the pan in its groove in the lower die of the sample press.
5. Put the flat side of the performing tool (2-3 inch metal wand with hole) against the upper die of the sample press.
6. Lower press lever handle. The upper die should lower down through the hole in the performance tool until it touches the pan.
7. Press down hard on the lever two or three times. Keep the upper die in contact with the pan between presses.
8. Raise the press lever handle.
9. Remove the pan with tweezers.
10. Weigh the sample and calculate the weight of the sample.
11. Repeat steps 1.-10. for PLGA and for a reference pan (no sample).
DSC Measurements
NOTE: These experiments should be done under the
direct supervision of a T.A. The T.A.
will operate the DSC and corresponding computer.
1. Turn on power to unit, heater, cooler, and computer.
2. Adjust N2 and He gas flow to appropriate rates.
3. Select appropriate module in computer.
4. Load the PLLA pan and the reference pan in the center of the square of the DSC chamber. Replace the three lids.
5. Run the sample using the following conditions: 20 °C start temperature, 10 °C/min ramp, 300 °C stop temperature.
6. Monitor the scan through the real-time plot.
7. Print out scans.
8. Record Tg (glass transition temperature) and Tm (melting temperature) for the sample.
9. Repeat Steps 1.-7. for the PLGA pan and the reference pan.