Tasks for November 5
- To run XRAY on ribbons
- To run DSC
- To measure absorbance of Malachite Green dye by ribbons at different time intervals
- To make beads
Synthesis of PVA-Clay beads
- Method followed as described by Mary Mendoza.
- 1.005 g PVA + 0.1074 g NaMT in 6 mL 10% HCl.
- 850 μL of 0.8% glutaraldehyde was added to 20 mL of ethyl acetate. The mixture was stirred at maximum speed on a stirrer.
- The PVA-clay-HCl solution was added to the ethyl acetate mixture in a drop wise manner.
- Depending on the conditions, microbeads should form between 2-3 minutes. As soon as the beads are visible, IMMEDIATELY ADD 25 mL of 0.2 M NaHCO3. Stir for at least 4 minutes, 15 minutes at most.
- Beads will be ready once a clear separation of the water and organic phase is observed. Beads will precipitate to the bottom of the beaker. There will still be some beads left in the organic solvent phase.
- Pour the contents into the falcon tube.
- Centrifuge for 1 min at 3000 rpm.
- Afterwards, remove the organic phase and suspend the beads in distilled water.
The high concentrations in this technique did not lead to good bead synthesis, since clumps formed. It is necessary to try again using 0.5 g PVA and 0.05 g Na MT, adding the glutaraldehyde in two intervals, as described by Mary.
Soaking Ribbons in Malachite Green
As described by Madeleine,
- UV-Vis time measurements were taken at:
- 0 min
- 10 min
- 30 min
- 60 min
- 120 min
- Approx. 24 h
- Weigh initial mass of ribbons, and final mass of ribbons after absorbance of MG dye.
- Initial mass: 0.4319 g
- Final mass:
- Note: films were soaked in 20 ppm malachite green. The MG dye solution was made from 80 ppm stock by Eleni.
- Starting volume of soaking solution: 10 mL.
X-ray Diffraction
To be carried out on fibers made on Oct. 31
- Want to determine whether ribbons retain clay
- Dry ribbons must be used
Sample Prep:
- Place ribbons on pXRD disk
- Press tape over film to hold in place, using a razor to cut off excess
- Sample in holder #2
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