User:Moira M. Esson/Notebook/CHEM-581/2012/09/05

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Objectives

  1. Prepare four dilute solutions from the stock solution of PVOH (MW 130,000), diluting by 0.75, 0.5, 0.25 and 0.125
  2. Measure the viscosity of PVOH (MW 130,000) at the concentrated stock solution and the four diluted concentrations
  3. Make PVOH (MW 22,000) films in H2O with 2-20wt% maleic or succinic acid and HCL or H3PO3


PVOH (MW 22,000) Films

General Protocol:

  1. Place 0.5g PVOH in a 10mL beaker with a small stir bar
  2. Add 3mL of water
  3. For each additional 0.5g, add an additional ~2mL of water
  4. Add the wanted weight percent of either maleic or succinic acid
  5. Add ~2 drops of HCl or H3PO4
    • Note: HCl and H3PO4 are corrosive
  6. Place on hot plate and heat to 70°C-80°C
  7. Stir and heat until dissolved(~15 min)
  8. Remove stir bar and any remaining gel
  9. Quickly pour solution into a Teflon dish. If excess gel is present remove with tweezers
  10. Allow film to air dry in fume hood


PVOH (MW 22,000) films prepared:

  • The following were combined in small beakers with 3mL of H2O
    • 0.5181g PVOH (MW 22,000), 10 wt% maleic acid(actual mass added was 0.0582g), 2 drops HCl
    • 0.5163g PVOH (MW 22,000), 10 wt% succinic acid(actual mass added was 0.5173g), 2 drops HCl
    • 1.0054g PVOH (MW 22,000), 15 wt% maleic acid(actual mass added was 0.1565g), 2 drops H3PO4
    • 1.0g PVOJ (MW 22,000), 15 wt% succinic acid, 2 drops H3PO4
  • An additional 2mL H2O was added to each solution (~10 minutes into heating) to aid in the dissolution of PVOH


Viscosity of PVOH (MW 130,000) Stock Solutions

  • The General Protocols for both serial dilutions and viscosity described on 08/31 were used


Stock Solution Calculations

  • Stock Solution Preparation for PVOH (MW 130,000)
Initial Mass [g] Additional Mass [g] Total Mass [g] Stock Volume [mL] Concentration [M] Weight percent [%]
2.0342 5.0203 7.0545 500 1.09E-4 1.41
  • Serial Dilution of PVOH (MW 130,000) Stock Solution
Dilution 'M1'[mol/L] 'V1' [mL] 'M2'[mol/L] 'V2' [mL]
1 1.09E-4 6.25 1.36-5 50
2 1.09E-4 12.5 2.71E-4 50
3 1.09E-4 25 5.43E-4 50
4 1.09E-4 35.5 8.14E-4 50


Viscosity Calculations

Viscosity of pure H2O at 24.5°C

Trial [ ] Time [s]
1 278.69
2 283.09
3 280.24
  • Average time = 280.67 s


Viscosity of 13.6 μM PVOH in H2O at 24.5°C

Trial [ ] Time [s]
1 263.59
2 263.12
3 263.01
  • Average time = 263.24 s


Viscosity of 27.1 μM PVOH in H2O at 24.5°C

Trial [ ] Time [s]
1 322.23
2 316.28
3 316.25
  • Average time = 318.25 s


Viscosity of 54.3 μM PVOH in H2O at 24.5°C

Trial [ ] Time [s]
1 400.68
2 398.66
3 398.73
  • Average time = 399.36 s


Viscosity of 81.4 μM PVOH in H2O at 24.5°C

Trial [ ] Time [s]
1 604.14
2 610.79
3 608.64
  • Average time = 607.86 s


Viscosity of 10.9 mM PVOH in H2O at 24.5°C

Trial [ ] Time [s]
1 955.96
2 957.38
3 967.46
  • Average time = 960.27 s


Notes

  • Another film was prepared specifically for IR analysis
    • Film was prepared using 0.1154g PVOH (MW 22,000) in 3mL H2O. After heating and dissolution(described in the General Protocol for preparation of films), film was poured into a large Teflon dish to create an extremely thin film




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