User:Moira M. Esson/Notebook/CHEM-581/2012/09/07

From OpenWetWare

(Difference between revisions)
Jump to: navigation, search
(DSC on PVOH Films)
(DSC on PVOH Films)
Line 75: Line 75:
# Cut and weigh out ~ 280 - 320mg of PVOH film sample to place in the Tzezo pan
# 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
# 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
+
# Use a Tzero press to secure and press the lid tightly over top the sample within the pan
# Open TA instrument explorer on computer. Select instrument to be used(in this case DSC)
# 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
# On control button, click event to create a new event
Line 81: Line 81:
# To modify a run, go to the experimental command and run a method edit
# 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
# Save all changes made to an experimental run in order to analyze samples
-
*Further notes on DSC program
 
-
# 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
 
<br>
<br>
To Collect the information from the DSC:
To Collect the information from the DSC:

Revision as of 20:32, 24 September 2012

Project name Main project page
Previous entry      Next entry

Objectives

  • Crosslink PVOH films through dehydration.
  • Prepare more PVOH (MW 130,000) films using HCl, H3<sub/>PO4,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 Film #3 Film #4 Film #5 Film #6
Mass PVOH used(g)1.08550.99641.03731.01061.01781.0215
Amount of [HCl] added(drop)020202
Amount of [H3<sub/>PO4 added(drop)202020
Amount of succinic acid added(g)00000.15280.1021
Amount of maleic acid added(g)000.15560.107100

Note:Complete dissolution of the PVOH required a longer amount of stirring(~2hours) and the addition of more deionized H2<sub/>O. To prompt complete dissolution, solutions were transferred to larger beakers(~50mL) with larger amounts of H2<sub/>O.

Crosslinking PVOH Films

Standard Protocol for Crosslinking of films:

  1. Weigh out ~0.2 grams of film
  2. Place measured film in round metal tray
  3. Place tray in oven at ~120 degrees C for 90 minutes

Crosslinked PVOH Films:

  1. PVOH(MW 22,000) with 15 wt% maleic acid
  2. PVOH (MW 22,000) with 15 wt% succinic acid

Solubility of PVOH Films

General Protocol:

  1. Place ~0.1g of film to be tested in a 100mL beaker.
  2. Add a stir bar to the beaker
  3. Place plastic stemless buchner funnel top above the film and stir bar
  4. Using a plastic pipette(s) to hold down the plastic mesh, add ~75mL of deionized H2<sub/>O to the beaker.
  5. Allow the film to completely dissolve
    • Gently stir the solution only with the stir plate. DO NOT add heat
  1. 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 Time [s]
1246.67
2253.48
3250.68
  • Average time:250.28 s

DSC on PVOH Films

DSC will be used to determine the different thermal transitions of the various films General Protocol for DSC:

  1. Weigh out the mass of a Tzero pan+Tzero lid(Record this measurement)
  2. Cut and weigh out ~ 280 - 320mg of PVOH film sample to place in the Tzezo pan
  3. Once each sample is placed in the pan, then place the lid onto the pan
  4. Use a Tzero press to secure and press the lid tightly over top the sample within the pan
  5. Open TA instrument explorer on computer. Select instrument to be used(in this case DSC)
  6. On control button, click event to create a new event
  7. To create a new event or run, click either the apply or append commands
  8. To modify a run, go to the experimental command and run a method edit
  9. Save all changes made to an experimental run in order to analyze samples


To Collect the information from the DSC:

  1. Click on export data file command
  2. Go to file and plot signals command
  3. Export the information obtained and save it(if possible save on flash drive)
  4. Go to signals command and select signal section, then time command underneath
  5. Select the analyze data command, then afterwards the integrate peaks command underneath
  6. Accept values established by integrating the peaks
  7. Click the analyze data command again to assign the glass transition value
  8. Select the area in which the glass transition point is seen and integrate that information
  9. Accept the values established from the glass transition point
  • 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

  1. 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
  1. 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.



Personal tools