OBJECTIVES
- Label and remove previous PVOH films from Teflon dishes
- Prepare more PVOH (MW 22K) films with both solid and liquid acid deviations (S - Maleic and Succinic; L - HCl and H3PO4) for film analysis: IR, DSC, solubility, crosslinking, acid catalyzed dehydration, film comparison, etc.
- Determine ratios and percentages in which solid acids will be added to the PVOH (MW 22K)
Deviated Acidic PVOH Film Preparations 3
Deviated HCl PVOH films prepared in water:
- In 10mL beaker, weigh out ~ 0.5 grams PVOH (MW 22K)
(Actual mass = 0.5181g)
- Then, using a graduated cylinder add ~ 3mL H2O to the beaker
- Next, at the fume hood add two drops of hydrochloric acid (HCl) to beaker solution
- Afterwards, calculate and weigh out a ~10%wt equivalent of maleic acid
- Add maleic acid equivalent to the acidic PVOH solution
(Actual Maleic Acid mass = 0.0582g)
- Repeat this procedure again; however use succinic acid as substitute for maleic acid.
(Actual PVOH mass = 0.5163g) (Actual Succinic Acid mass = 0.0571g)
Deviated H3PO4 PVOH films prepared in water:
- In another 10mL beaker, weigh out ~ 1 gram PVOH (MW 22K)
(Actual mass = 1.0054g)
- Then, using a graduated cylinder add ~ 6mL H2O to the beaker
- Next, at the fume hood add two drops of phosphoric acid (H3PO4) to beaker solution
- Afterwards, calculate and weigh out a ~15%wt equivalent of maleic acid
- Add maleic acid equivalent to the acidic PVOH solution
(Actual Maleic Acid mass = 0.1565g)
- Repeat this procedure again; however use succinic acid as substitute for maleic acid.
(Actual PVOH mass = 1.0125g) (Actual Succinic Acid mass = 0.1519g)
Standard PVOH Film Protocol:
- After adding and combining PVOH (MW 22K) in small beakers with H2O and all acids (HCl, H3PO4, maleic and succinic), add stir bars and prepare to stir solutions.
- On hot plate, stir and heat all beaker solutions at 70-80°C for ~ 12 min or until all solids dissolve.
- Once PVOH and acidic solids dissolve in solution, pour each solution in Teflon dishes to sit, cool, and dry in a fume hood for ~ 2 days.
Notes
- An additional 2-3 mL H2O was added to each solution to aid the dissolving of the PVOH
- Heat was reduced when solutions began to boil too rapidly
- As solutions heated, beakers containing the strong acids (HCl) left burn marks at the bottom of solution -- slightly tinting the PVOH solutions brown
- While transferring solutions to Teflon dishes, loss of sample within the small beakers (sample loss = incomplete sample transfer)
- PVOH (MW 22K) films w/just liquid acids were harder and more rigid than PVOH (MW 22K) films w/ both liquid and solid acids added.
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