Objectives
- Crosslink PVOH films through dehydration.
- Prepare more PVOH (MW 130,000) films using HCl, H3PO4,and maleic or succinnic acid
- Run solubility tests of crosslinked and uncrosslinked PVOH films
- Run Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning calorimetry(DSC) on PVOH films
PVOH(MW 130,000) Films
- The standard protocol for PVOH Film preparation was used.
- Note: If indicated that acid was added
Prepared PVOH(MW 130,000) Films
| '
|
Film #1
|
Film #2
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Film #3
|
Film #4
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Film #5
|
Film #6
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| Mass PVOH used(g) |
1.0855 |
0.9964 |
1.0373 |
1.0106 |
1.0178 |
1.0215
|
| Amount of [HCl] added(drop) |
0 |
2 |
0 |
2 |
0 |
2
|
| Amount of [H3PO4 added(drop) |
2 |
0 |
2 |
0 |
2 |
0
|
| Amount of succinic acid added(g) |
0 |
0 |
0 |
0 |
0.1528 |
0.1021
|
| Amount of maleic acid added(g) |
0 |
0 |
0.1556 |
0.1071 |
0 |
0
|
Note:Complete dissolution of the PVOH required a longer amount of stirring(~2hours) and the addition of more deionized H2O. To prompt complete dissolution, solutions were transferred to larger beakers(~50mL) with larger amounts of H2O.
Crosslinking PVOH Films
Standard Protocol for Crosslinking of films:
- Weigh out ~0.2 grams of film
- Place measured film in round metal tray
- Place tray in oven at ~120 degrees C for 90 minutes
Crosslinked PVOH Films:
- PVOH(MW 22,000) with 15 wt% maleic acid
- PVOH (MW 22,000) with 15 wt% succinic acid
Solubility of PVOH Films
General Protocol:
- Place ~0.1g of film to be tested in a 100mL beaker.
- Add a stir bar to the beaker
- Place plastic stemless buchner funnel top above the film and stir bar
- Using a plastic pipette(s) to hold down the plastic mesh, add ~75mL of deionized H2O to the beaker.
- Allow the film to completely dissolve
- Gently stir the solution only with the stir plate. DO NOT add heat
- Once the film is completely dissolved, test the viscosity of the solution three times
Viscosity of uncrosslinked PVOH(MW 22,000) 15wt% maleic acid
| Trial
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Time [s]
|
| 1 |
246.67
|
| 2 |
253.48
|
| 3 |
250.68
|
DSC on PVOH Films
DSC will be used to determine the different thermal transitions of the various films
General Protocol for DSC:
- Weigh out the mass of a Tzero pan+Tzero lid(Record this measurement)
- Open TA instrument explorer on computer. Select instrument to be used(in this case DSC)
- On control button, click event to create a new event
- Set flange temperature at -80°C
- 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 5 and 6 one time
- About 3 mg ± 20% PVOH film was placed in a DSC pan.
- Uncrosslinked PVOH (MW 22000) + 15% maleic acid + H3PO4
- Pan mass: 49.42 mg
- Sample mass: 3.13 mg
- Uncrosslinked PVOH (MW 22000) + 15% succinic acid + H3PO4
- Pan mass: 51.02 g
- Sample mass: 3.15 g
- 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(able to observe on graph by looking at the change in slope). 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. A reaction may have occurred at these temperatures or a phase change may have occurred
- Graph of heat flow of uncrosslinked PVOH (MW 22000) + H3PO4.
- A glass transition was observed at 82.61°C.
- A sharp peak was observed at 179.47°C. This may be caused by a reaction or phase change.
Notes
- For Solubility still need to test:
- PVOH (MW 22,000) uncrosslinked with 15wt% succinnic acid
- PVOH (MW 22,000) uncrosslinked with 10wt% maleic acid
- PVOH (MW 22,000) crosslinked with 15wt% maleic acid
- PVOH (MW 22,000) crosslinked with 15wt% succinnic acid
- PVOH (MW 22,000) uncrosslinked with 10wt% succinnic acid
- PVOH (MW 22,000) uncrosslinked
- PVOH (MW 22,000) crosslinked
- For films need to prepare:
- PVOH (MW 130,000) uncrosslinked with 15wt% maleic acid
- PVOH (MW 130,000) uncrosslinked with 10wt% maleic acid
- PVOH (MW 130,000) crosslinked with 15wt% maleic acid
- PVOH (MW 130,000) crosslinked with 10wt% maleic acid
- PVOH (MW 130,000) uncrosslinked with 15wt% succinic acid
- PVOH (MW 130,000) uncrosslinked with 10wt% succinic acid
- PVOH (MW 130,000) crosslinked with 15wt% succinic acid
- PVOH (MW 130,000) crosslinked with 10wt% succinic acid
- PVOH (MW 130,000) uncrosslinked(and crosslinked) with 15wt% succinic acid and HCl
- PVOH (MW 130,000) uncrosslinked(and crosslinked) with 10wt% succinic acid and H3PO4
- PVOH (MW 130,000) uncrosslinked(and crosslinked) with 15wt% maleic acid and HCl
- PVOH (MW 130,000) uncrosslinked and crosslinked with 10wt% maleic acid and H3PO4
- PVOH (MW 22,000) uncrosslinked and crosslinked with 10wt% maleic acid
- PVOH (MW 22,000) uncrosslinked and crosslinked with 15wt% maleic acid
- PVOH (MW 22,000) uncrosslinked and crosslinked with 10wt% succinic acid
- PVOH (MW 22,000) uncrosslinked and crosslinked with 15wt% succinic acid
- PVOH (MW 22,000) uncrosslinked and crosslinked with 10wt% maleic acid and H3PO4
- PVOH (MW 22,000) uncrosslinked and crosslinked with 15wt% maleic acid and HCl
- PVOH (MW 22,000) uncrosslinked and crosslinked with 10wt% succinic acid and H3PO4
- PVOH (MW 22,000) uncrosslinked and crosslinked with 15wt% succinic acid and HCl
Observations
- Crosslinked PVOH films became more rigid and changed color from transparent to faintly yellow-brown.
- The viscometer used for previous tests was discovered to be cracked. A new viscometer was subsequently used.
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Project name
