User:Melissa Novy/Notebook/CHEM-581/2012/09/07

Objectives

• Crosslink PVOH films.
• Make more PVOH (MW 130000) films with strong acid and maleic or succinic acid.
• Run solubility tests on crosslinked and uncrosslinked PVOH films.
• Run FTIR and DSC on PVOH films.

PVOH (MW 22,000) Films

PVOH (MW 130,000 Films

Solubility of PVOH Films

• 0.1023 g of uncrosslinked PVOH (MW 22000), 15 wt% maleic acid, H₃PO₄ was dissolved in 75 mL H₂O.
• The viscosity of the solution was tested:

• Average time: 250.28 s

DSC on PVOH Films

• 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. 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.
• 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, possibly due to a reaction or phase change.

• Procedure:
  1. Equilibrate at 20.00°C.
  2. Ramp 20.00°C/min to 240.00°C.
  3. Ramp 20.00°C/min to 20.00°C.
  4. Repeat steps 2 and 3 one time.

Notes

• Films were crosslinked in the oven at 120°C for 90 minutes.
• 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.