OBJECTIVES
- Observe and learn about methods, DSC and FTIR, for testing and analysis
- Prepare PVOH samples for DSC testing and analysis
- Collect all data and experimental results from DSC testing and analysis
FTIR Program Instructions
- Start the OPUS program
- Go to and select the Measurement command
- Afterwards select and run the Background Measurement command
- After the background is measured for a particular sample, create a sample file name (PVOH 22K)
- Place the cut PVOH sample or film to be measured in the Universal Sample Holder
- Then select and run the Sample Measurement Command
- Next, when a graph with peaks appears, hit the Save As command
- While saving is occurring for the file, add a pathway (CHEM 581) and a directory name (MKM)
- Finally officially save the sample measurement and file information
- Use the copy and paste command to create images under the picture program to link to your online notebook
- Create folder a to save the image under the picture program on the computer and then hit the Save As command
(Be sure to save the sample / graph image as a jpeg file for convenience)
Data Collection and Results: FTIR PVOH 22K Thin Film
- Loss of resolution around 3700 to 3000 cm-1 indicates that the PVOH film is too thick for FTIR. The analysis will be redone in the future with either the same PVOH film suspended in KBr or with a a thinner PVOH film.
DSC Program and Instrument Instructions
- Select either service or thermal when turning the instrument on
- Click TA Instrument Explorer on the screen to show which instruments are currently running
- Turn on the gas, but keep it to a minimal amount
- Click on a specific machine to choose which machine is needed to run samples
- After selecting the correct machine needed, click on the control command to turn on an event
- To create a new event or run, click either the apply or append commands
- To modify a run, go to the experimental command and run a method edit
- Save all changes made to an experimental run in order to analyze samples
DSC Sample Preparation Instructions
- Select a Tzezo pan and lid to weigh out for sample preparation
- Record the total mass of both the pan and lid for each sample prepared
- Cut and weigh out ~ 280 - 320mg of PVOH film sample to place in the Tzezo pan
- Once each sample is placed in the pan, then place the lid onto the pan
- Use a Tzezo press to secure and press the lid tightly over top the sample within the pan
- Label each sample prepared for DSC testing and use DSC instrument and software to run analysis
(make sure open slot numbers where samples are placed in the DSC instrument are recorded)
PVOH Samples Prepared For DSC Analysis
| Film Type
|
Sample Mass (mg)
|
Pan / Lid Mass (mg)
|
| Plain PVOH 22K |
3.20 |
49.78
|
| Uncrosslinked PVOH 22K, 10% maleic acid, HCl |
2.90 |
50.41
|
| Uncrosslinked PVOH 22K, 10% succinic acid, HCl |
2.92 |
49.26
|
| Uncrosslinked PVOH 22K, H3PO4 |
3.15 |
51.02
|
| Uncrosslinked PVOH 22K, 15% maleic acid, H3PO4 |
3.13 |
49.42
|
| Crosslinked PVOH 22K, 15% maleic acid, H3PO4 |
3.13 |
49.96
|
| Crosslinked PVOH 22K, 15% succinic acid, H3PO4 |
3.10 |
49.70
|
DSC Data Collection Instructions
- Open the DSC program
- Go to export data file command
- Then go to file and plot signals command
- Export the information obtained and save it
- Go to signals command and select signal section, then time command underneath
- Select the analyze data command, then afterwards the integrate peaks command underneath
- Next, accept the values established from integrating the peaks
- Then select the analyze data command again to assign the glass transition value
- Select the area in which the glass transition point is seen and integrate that information
- Next, accept the values established from the glass transition point
Data Results of PVOH Films
- Graph of heat flow of uncrosslinked PVOH (MW 22000) + 15% maleic acid + H3PO4.
- Two possible glass transitions at 105.79°C and at 155.16°C were observed. Running DSC on the sample a second time may clarify which is the true glass transition temperature.
- Two sharp peaks at 144.66°C and at 155.64°C were observed. They may indicate that two reactions or phase changes took place at those temperatures.
- Procedure:
- Equilibrate at 20.00°C.
- Ramp 20.00°C/min to 240.00°C.
- Ramp 20.00°C/min to 20.00°C.
- Repeat steps 2 and 3 one time.
Notes
- For DSC experiment, the flange temperature that must be maintained has to be ~ 80°C
- When physically turning on the actual instrumentation, be extremely cautious because prongs in the area can be easily bent
|
PVOH Research
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