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

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)

• Serial Dilution of PVOH (MW 130,000) Stock Solution

Viscosity Calculations

Viscosity of pure H₂O at 24.5°C

• Average time = 280.67 s

Viscosity of 13.6 μM PVOH in H₂O at 24.5°C

• Average time = 263.24 s

Viscosity of 27.1 μM PVOH in H₂O at 24.5°C

• Average time = 318.25 s

Viscosity of 54.3 μM PVOH in H₂O at 24.5°C

• Average time = 399.36 s

Viscosity of 81.4 μM PVOH in H₂O at 24.5°C

• Average time = 607.86 s

Viscosity of 10.9 mM PVOH in H₂O at 24.5°C

• 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