OBJECTIVES
ACCIDENTALLY PLACED THIS ENTRY ON THE FEBRUARY 4th; HOWEVER, THIS ENTRY SHOULD BE UNDER FEBRUARY 6th. THANK YOU.
- Begin preparing polyvinyl alcohol microsperes for experimental analysis
- Filter surfactant exchanged modified clays
- Complete freeze and thaw crosslinked clay cycle #1
90:10 PVOH Clay Microsphere Preparations
*Reaction should be carried out using a reflux condenser and a thermostatic water bath of 55°C.
- Dissolve ~ 1.0g total of PVOH 146K and clay additive selected (laponite) in 5mL hot deionized H2O
- Acidify the solution using 0.25mL 0.5M H2SO4
- Dissolve ~ 0.6g cellulose acetate butyrate(CAB) in 25mL 1,2-dichloroethane within a round bottom flask
- Pour the acidified PVOH 146K solution into the 25mL 1,2-dichloroethane solution within the clean round bottom flask
- Stir 1,2-dichloroethane, CAB, and PVOH 146K solution for 30 minutes
- After 30 minutes of stirring, add 0.75mL glutaraldehyde to the solution
- After the addition of glutaraldehyde, allow the reaction to carry out for 3 additional hours at 55°C
- Filter the produced microspheres from the solution using a a sintered glass filter and a vacuum
- Wash the collected microspheres using ~ 2-3mL of the following solvents in the following order:
* 1,2-dichloroethane
* acetone
* hot water
* cold water
* methanol
- Scrape off all of the collected microspheres into a small glass vial. Leave the lid off of the small glass vial.
- Freeze microspheres in liquid nitrogen for ~ 2 minutes
- Place on [ask Dr. Hartings name of machine again] overnight to completely dry
* The following procedure was adapted from the article Poly(vinyl alcohol) microspheres with pH- and thermosensitive properties as temperature-controlled drug delivery [1]
Important 1,2 Dichloroethane and Glutaraldehyde Safety
- Dimethyl Sulfoxide is toxic colorless liquid (78.13g / mole)
- Avoid all dimethyl sulfoxide skin contact by wearing gloves and googles
- Dimethyl Sulfoxide should be kept in the flammable cabinet when not in use
- When in use, dimethyl suloxide should be kept in the fume hood
- If spilled, wipe up dimethyl sulfoxide with paper towel while wearing gloves
- Keep all spills of dimethyl sulfoxide contained in the fume hood
- Wash hands after removing gloves that were in contact with dimethyl sulfoxide
Clay Exchanged Solutions & Vacuum Filtration Procedures
The clays being filtered are the clays that were prepared on 2/1/13
Setup of a vacuum filtration system:
* Clean 250mL Erlenmeyer Filter Flask
* Large Buchner Funnel
* Whatman #42 Filter Paper
* Long Secure Rubber Hose
- Filter a clay solution selected using the vacuum filtration system setup
- Attach all parts of the apparatus to the vacuum filtrator system
- Place a piece of Whatman #42 filter paper in the Buchner Funnel
- Turn on the vacuum filtrator system
- Check the suction rate to ensure that enough pressure is applied
- Pour an exchanged clay solution into the Buchner funnel
- Allow vacuum filtration to continue until the clay is completely dry
- Discard the aqueous filtrate solution and place it in a labeled waste container
- Collect the soil filtrate on the filter paper and scrape it into a small labeled metal pan
- Place metal pan with the soil filtrate in the oven to dry for ~ 2-3 days
- Wash all glassware and equipment first with H2O and then with acetone for later use
Notes
ACCIDENTALLY PLACED THIS ENTRY ON THE FEBRUARY 4th; HOWEVER, THIS ENTRY SHOULD BE UNDER FEBRUARY 6th. THANK YOU.
- Clays previously prepared on 2/1/13 only exchanged for ~ 5 days rather than a week.
- While attempting to filter the clays, due to vacuum filtration moving rather slowly during separation, clays only were filter for ~ 2.5 hours before actually being placed in the oven.
- The temperature of the oven when the clays were placed in was ~ 90°C.
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PVOH Research
