1. Set the oven temperature to 25 oC and wait 10 minutes. Zero the gap with the clean parallel plates at 25 oC before preparing sample. Do not remove or adjust the top plate after it has been zeroed.
2. Add the clip to the bottom parallel plate so that the sample will not melt off of the plate. Add enough sample so that there will be about a 1mm thickness when it is melted.
3. Melt the sample in a vacuum oven until the sample is melted and all of the gas is out of the sample. Set the timer so that the oven will turn off at around 12-3am.
4. Remove the sample from the oven when the temperature is below 60 oC.
5. Remove the clip from around the sample so that only the plate is remaining.
6. Insert the thermocouple on the base of the rheometer and turn until is falls into position.
7. Add the bottom plate, press down, and hand tighten into position. Use the tool to tighten ¼ turn after hand tight.
8. Lower the top plate into position until almost touching the sample.
9. Pull oven into place and close the oven door.
10. Make sure the liquid N2 valve is open and that the cylinder pressure is above 20 psi. Also check to see the that liquid level is not empty.
11. On the instrument control panel, turn the environmental controller off and liquid N2 dewar on.
12. When the liquid N2 dewar is ready, turn the environmental controller on to the desired temperature (above the melting temperature) and turn the oven on to liquid nitrogen control.
13. Gently lower the gap until the desired height. (The normal force should not go above 100 in either direction). Adjust for the 2.6 ?m / oC that the gap changes from the temperature that it was zeroed at.
14. Open the oven and look to see that the sample is gently bulging out at each side of the plate.
15. Wait ten minutes for the sample to settle.
16. Press the green start button. Choose parallel plate geometry and enter in the correct diameter and gap (at temp of zeroing). In test set-up, choose dynamic strain sweep, strain controlled. Choose w = 1 rad/sec, enter in the correct temperature, strain rate from 0.01 to 100, 5 points per decade. In the end of test field, all options should be turned off. In the options field, no delay should be checked.
17. Begin the test. Look to find strain range where viscosity does not change. The torque also should be greater than 0.02 g-cm and G’ and G’’ should both be positive. Choose an appropriate value of the strain that meets these requirements (torque ~ 1 is ideal).
18. Hit the start button. Chose dynamic frequency sweep. Enter in the correct strain value and temperature. The frequency range should be 100 to 0.1, 10 points per decade. Make sure that the end of test options delay are not checked.
19. For a Newtonian fluid, the slope of G’ is 2, G’’ is 1, and ? is flat.
20. After the test is done, change the temperature to the next desired temperature and adjust the gap accordingly. Wait 10 minutes before starting the tests.
21. To shut down, raise the temperature until it is above the melting temperature. Then manually increase the gap until it is 6 mm. Disconnect the polymer sample so that the two plates are no longer connected before cooling down to room temperature.
22. Turn off the environmental controller and N2 dewar. The dewar will make a popping sound when the pressure is released.
23. Close the liquid nitrogen valve.