< User:Moira M. Esson | Notebook | CHEM-581 | 2013 | 02
(Difference between revisions)
| Project name
|| Main project page|
Previous entry Next entry
- Run DSC on samples prepared on 2013/02/06.
- Finish preparing all microspheres using PVA MW 146,000-186,000.
- Remove organic layer from microspheres prepared on 2013/02/15.
- The general protocol for DSC was followed.
Parameters for DSC samples:
- Equilibrate -40°C.
- Ramp 20°C to 240°C.
- Ramp down 20°C to (-40°C).
- Repeat segement #2
- All DSC data will be uploaded next lab session.
- The PVA MW 146,000-186,000: Lamponite prepared on Wednesday formed completely separate layers during the 24 hour thaw process. Before placing back into the freezer, the samples were sonicated and refrozen in liquid nitrogen. For the remaining freeze thaw processes, the samples will spend 20 hours in the freezer and 4 hours out of the freezer. After the 4 hours thawing, the samples will be sonicated, refrozen in liquid nitrogen, and replaced in a freezer at -20°C.
- The samples were prepared using the general protocol described on 2013/02/20 except a freeze thaw cycle of 20 hours freezing, and 4 hours thawing was used.
PVA MW 146,000-186,000 Microspheres
|Composition of microspheres
||Mass of PVA(g)
||Mass of clay(g)
||Volume of distilled H2O(mL)
||Volume of safflower oil(mL)
| 90:10 PVA:50% exchanged NaMT||0.90020||0.10330||25||50
| 50:50 PVA:50% exchanged NaMT||0.50620||0.50090||25||50
| 90:10 PVA:NaMT||0.90160||0.10360||25||50
| 50:50 PVA:NaMT||0.50250||0.49980||30||50
| 50:50 PVA:110% Lamponite||0.50960||0.50460||35||50
- The samples containing NaMT seemed to have larger spheres in the emulsion.
- The samples containing NaMT seemed to require more time to completely freeze in liquid nitrogen.
Organic layer removal
- The three microsphere samples that were completely thawed were placed in a freezer at -20°C for 4 hours. This was to induce the freezing of the aqueous, PVA/clay layer. The organic, mineral oil layer, however, remained unfrozen.
- The mineral oil layer was poured into the appropriate waste container.
- The microspheres were then rinsed with 10mL of hexanes three times to remove any excess mineral oil present in the sample.
- The microspheres were left in the fume hood over night for the complete evaporation of the hexanes from the sample.