User:Melissa Novy/Notebook/CHEM-581/2012/09/05

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Objectives

  • Make PVOH (MW 22,000) films with 2-20 wt% maleic or succinic acid and HCl or H3PO4.
  • Measure viscosity of PVOH (MW 130,000) at concentrations of 13.6 μM, 27.1 μM, 54.3 μM, and 81.4 μM.
  • Run IR on PVOH films.

PVOH (MW 22,000) Films

  • The following were combined in beakers with 3 mL H2O, then heated and stirred:
    • 1.0 g PVOH, 15 wt% maleic acid, 2 drops H3PO4
    • 1.0 g PVOH, 15 wt% succinic acid, 2 drops H3PO4
    • 0.5 g PVOH, 10 wt% maleic acid, 2 drops HCl
    • 0.5 g PVOH, 10 wt% succinic acid, 2 drops HCl
  • An additional 2 mL H2O was added to each solution to aid in dissolution of the PVOH.

Viscosity of PVOH (MW 130,000) Stock Solutions

  • Viscosity Protocol
    1. Pour about 10 mL of the solution into the viscometer.
    2. Wash the viscometer by drawing the solution into the viscometer past the top of the lower bulb, then draining it.
    3. Repeat this two more times, then discard the solution.
    4. Pour another 10 mL of solution into the viscometer and draw it up past the top of the lower bulb.
    5. Let the solution drain from the viscometer, starting a stopwatch as the bottom of the meniscus passes the first mark on the viscometer.
    6. Stop the stopwatch as the bottom of the meniscus passes the second mark on the viscometer.
    7. Repeat steps 4 through 6 twice more, to obtain the average time, in seconds, for the solution to pass between the two marks.


Viscosity of pure H2O

Trial [ ] Time [s]
1278.69
2283.09
3280.24
  • Average time = 280.67 s


Viscosity of 13.6 μM PVOH in H2O

Trial [ ] Time [s]
1263.59
2263.12
3263.01
  • Average time = 263.24 s


Viscosity of 27.1 μM PVOH in H2O

Trial [ ] Time [s]
1322.23
2316.28
3316.25
  • Average time = 318.25 s


Viscosity of 54.3 μM PVOH in H2O

Trial [ ] Time [s]
1400.68
2398.66
3398.73
  • Average time = 399.36 s


Viscosity of 81.4 μM PVOH in H2O

Trial [ ] Time [s]
1604.14
2610.79
3608.64
  • Average time = 607.86 s


Viscosity of 10.9 mM PVOH in H2O

Trial [ ] Time [s]
1955.96
2957.38
3967.46
  • Average time = x s

Observations

  • PVOH (MW 130,000) films were harder and more rigid than PVOH (MW 130,000) films with added acid.
  • PVOH films with added HCl turned brown during heating.



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