User:Anh Do/Notebook/CHEM 481 Polymer/2016/09/07

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Making Beads using Bentonite

1. Protocol

  • Using this protocol, scaled to produce 4.5 g of beads
    • Beads contains 10% clay
      • Volumn of bentonite 3wt% needed: 45*0.1*100/3 = 15 mL
    • Mass of PVOH meassured: 4.5005 g
    • Volumn of HCl 1.45M needed: 48*1.0/1.45 = 33 mL

2. Observations

  • Beads were not formed.
  • PVOH/Bentonite solution formed large clumbs in the container

3. Note

  • Glutaraldehyde should be added after all PVOH/Bentonite solution is added to ethyl acetate. This way, the crosslinking process can happen more smoothly.

PVOH film with Bentonite solution

  • Mass of PVOH needed: 1 g
    • Mass of PVOH meassured: 1.0006 g
  • Volumn of bentonite 3wt% needed: 0.1/3*100 = 3.33 mL
  • Volumn of water needed: 8.67 mL
    • 12 mL - 3.33 mL bentonite solution = 8.67 mL water
  • Follow the same procedure


Crosslink films

1. Protocol

  • Use a spoon to remove the films from the Teflon disk starting from the edges
  • Use [this] protocol to crosslink the films

2. Observations (adapted from Sarah's notes)

  • Mass of air dried films:
    • PVOH+ Bentonite + Glutaraldehyde: 0.50790 g
    • PVOH + Bentonite+ Glutaraldehyde + Glyoxal: 0.53745 g
  • Heat acidic sulfate solution to 70°C
  • Place films in heated solution for 60 min
    • Used lowest spin setting to minimize entanglement since the stir bar interfere with the films
    • Plastic buchner funnel can be used to separate bar from film, but 75 mL solution needed
  • Rinsed films with deionized water (~ 5 sec)
    • Glutaraldehyde film was soft, but had good integrity (clear, colorless)
    • Glyoxal film had collapsed into sticky gel-like clump (translucent - white color)
  • Placed films in 50 mL 1 M HCl at 70°C for 60 min (requires preheat; plan accordingly)
    • Both films were transparent and rubbery
    • Edges can break; care needed when handling with tweezers
  • Rinsed films in water (~ 5 sec) and soak for 10 min
  • Place films in 0.2 M NaHCO3 for 30 min
  • Rinse films in water (~ 5 sec) and soak for 10 - 20 min
  • Final rinse (~ 5 sec) and air dry for 2 days
  • Noted film appearances prior to drying
    • Glutaraldehyde film still had good integrity
    • Glyoxal film was a clump and may have lost mass
    • Both films had similar textures & colors: transparent & rubbery

Next Lab

  • Remake beads but add glutaraldehyde later
  • Remake beads with bentonite powder


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