User:Karlena L. Brown/Notebook/PVOH Research/2013/02/04

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(OBJECTIVES)
(90:10 PVOH Clay Microsphere Preparations)
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* Complete freeze and thaw crosslinked clay cycle #1
* Complete freeze and thaw crosslinked clay cycle #1
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==90:10 PVOH Clay Microsphere Preparations==
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==90:10 PVOH Clay Microsphere Preparations=
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# In 10mL beaker, weigh out ~ 0.9 grams PVOH (MW 146K)
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'''*Reaction should be carried out using a reflux condenser and a thermostatic water bath of 55°C.'''
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# Then, using a graduated cylinder add ~ 6 mL H<sub>2</sub>O to the beaker
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# Dissolve ~ 1.0g total of PVOH 146K and clay additive selected (laponite) in 5mL hot deionized H<sub>2</sub>O
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# After adding and combining PVOH (MW 146K) in a small beaker with H<sub>2</sub>O, add a stir bar to stir solution
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# Acidify the solution using 0.25mL 0.5M H<sub>2</sub>SO<sub>4</sub>
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# On hot plate, stir and heat beaker solutions at 70-80°C for ~ 1 hour or until PVOH dissolves
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# Dissolve ~ 0.6g cellulose acetate butyrate(CAB) in 25mL 1,2-dichloroethane within a round bottom flask
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# Once PVOH solids thoroughly dissolve in solution, then add ~ 0.1 gram of clay to the solution
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# Pour the acidified PVOH 146K solution into the 25mL 1,2-dichloroethane solution within the clean round bottom flask
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# Continue stirring the solution until a homogenous mixture forms and the clay is equally distributed
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# Stir 1,2-dichloroethane, CAB, and PVOH 146K solution for 30 minutes
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# Allow the solution to cool to 40-50°C, and then remove the stir bar from the solution
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# After 30 minutes of stirring, add 0.75mL glutaraldehyde to the solution
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# Then place the solution into the freezer at -20°C to freeze for ~ 24 hours
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# After the addition of glutaraldehyde, allow the reaction to carry out for 3 additional hours at 55°C
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# The next day, remove the hydrogels in the freezer in order that the substances can thaw for ~ 24 hours
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# Filter the produced microspheres from the solution using a a sintered glass filter and a vacuum
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# Continue the crosslinking freezing and thawing method for ~ 3 days
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# Wash the collected microspheres using ~ 2-3mL of the following solvents in the following order:
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        '''* 1,2-dichloroethane'''
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        '''* acetone'''
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        '''* hot water'''
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        '''* cold water'''
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        '''* methanol'''
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# Scrape off all of the collected microspheres into a small glass vial. Leave the lid off of the small glass vial.
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# Freeze microspheres in liquid nitrogen for ~ 2 minutes
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# Place on [ask Dr. Hartings name of machine again] overnight to completely dry
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'''* The following procedure was adapted from the article Poly(vinyl alcohol) microspheres with pH- and thermosensitive properties as temperature-controlled drug delivery [http://www.sciencedirect.com/science/article/pii/S1742706110002151]'''
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<br>
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==Important 1,2 Dichloroethane and Glutaraldehyde Safety==
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* Dimethyl Sulfoxide is toxic colorless liquid (78.13g / mole)
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* Avoid all dimethyl sulfoxide skin contact by wearing gloves and googles
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* Dimethyl Sulfoxide should be kept in the flammable cabinet when not in use
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* When in use, dimethyl suloxide should be kept in the fume hood
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* 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==
==Clay Exchanged Solutions & Vacuum Filtration Procedures==

Revision as of 19:00, 10 February 2013

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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.

  1. Dissolve ~ 1.0g total of PVOH 146K and clay additive selected (laponite) in 5mL hot deionized H2O
  2. Acidify the solution using 0.25mL 0.5M H2SO4
  3. Dissolve ~ 0.6g cellulose acetate butyrate(CAB) in 25mL 1,2-dichloroethane within a round bottom flask
  4. Pour the acidified PVOH 146K solution into the 25mL 1,2-dichloroethane solution within the clean round bottom flask
  5. Stir 1,2-dichloroethane, CAB, and PVOH 146K solution for 30 minutes
  6. After 30 minutes of stirring, add 0.75mL glutaraldehyde to the solution
  7. After the addition of glutaraldehyde, allow the reaction to carry out for 3 additional hours at 55°C
  8. Filter the produced microspheres from the solution using a a sintered glass filter and a vacuum
  9. Wash the collected microspheres using ~ 2-3mL of the following solvents in the following order:
       * 1,2-dichloroethane
       * acetone
       * hot water
       * cold water
       * methanol
  1. Scrape off all of the collected microspheres into a small glass vial. Leave the lid off of the small glass vial.
  2. Freeze microspheres in liquid nitrogen for ~ 2 minutes
  3. 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
  1. Filter a clay solution selected using the vacuum filtration system setup
  2. Attach all parts of the apparatus to the vacuum filtrator system
  3. Place a piece of Whatman #42 filter paper in the Buchner Funnel
  4. Turn on the vacuum filtrator system
  5. Check the suction rate to ensure that enough pressure is applied
  6. Pour an exchanged clay solution into the Buchner funnel
  7. Allow vacuum filtration to continue until the clay is completely dry
  8. Discard the aqueous filtrate solution and place it in a labeled waste container
  9. Collect the soil filtrate on the filter paper and scrape it into a small labeled metal pan
  10. Place metal pan with the soil filtrate in the oven to dry for ~ 2-3 days
  11. 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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