Complete tasklist
- Finish crosslinking for Glyoxal film. See protocol here
- Redo beads formation, using powder clay instead of clay solution
- MG calibration curve
- Carefully examine the bottom of your bottle. Any solid particles present?
- We will use UV/Vis spectroscopy to measure MG concentrations
- The maximum absorption for any UV/Vis analysis should be 1
- You need at least 5 concentrations (as evenly distributed as possible) to make a standard curve
- PVOH film characterization
- Swelling characteristics are examined by mass before and after drying in an oven
- Crystallinity is examined using XRD
- Thermal transitions are examined using DSC
- PVOH film preparation
- Repeat the preparation of film containing clay, but use 3 wt% solution to replace some of the water.
3 wt% solution instead of powder for the following protocol:
1 g PVOH + 0.1 g bentonite + 0.5 mL glutaraldehyde in 12 mL water
wt% = weight of solute/ weight of solvent*100
3 wt% = 3 g bentonite / 97 ml water
0.1 g * 97 ml/3 g bentonite = 3.23 ml bentonite solution, 12 - 3.23 ml water
concentrated HCl is ~ 37 percent . To get 30 ml 10 percent, we need to dilute it with water .
21. 9 ml water + 8.1 ml HCl
multiplied by 5 -- ~100 ml water , 40 ml acid
Chemicals
- Polyvinyl alcohol PVOH = PVA
- Clay: Bentonite or NaMT
Bead formation
Make PVOH - clay - HCl solution
- use powder clay
- multiply the following by 4 to yield ~4.5 g of beads:
1.0016g PVOH and 0.1114g clay in 12 mL of HCl
Protocol:
- 30 mL of ethyl acetate + 500 uL of glutaraldehyde
- Add your PVA-clay (approximately .5 g of PVA and .051-.055g NaMT) in a dropwise manner. Immediately start timing the reaction for 2 minutes when you do the first drop.
- After 2 minutes, slowly add 7 mL of 0.2 M NaHCO3.
- Once completed, transfer to a falcon tube and centrifuge for 1 minute at 3000 rpm, rotor 41.
- When beads are separated from the organic phase, pipet out the organic phase and re-suspend the beads in distilled water.
Observations
Glyoxal film formed a gel in HCl, which means crosslinking was not as successful as desired. We will discard it.
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