User:Douglas M. Fox/Notebook/AU CHEM-581 F2012 Lab Support/2012/08/22

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PVOH Dialdehyde Crosslinking

  • Record mass of air dried films:
    • Glutaraldehyde: 0.50790 g         Glyoxal: 0.53745 g
  • Heat acidic sulfate solution to 70°C
  • Place films in heated solution for 60 min
    • Stir bar interfered with films
    • Used lowest spin setting to minimize entanglement
    • 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 now 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

PVOH Solubility

  • 150 mL tall form beaker, 40 mm stirbar, 43 mm buchner funnel top (upside down), plastic pipet to wedge funnel in place
  • 75 mL water & placed PVOH + MA (H2SO4) on base of funnel
    • Air dry mass of film: 0.46596 g
  • Stirred 2 hrs on black stir plate (plate warms to ~35°C over time)
  • Film remained hard, but portions of each side had partially separated from the bulk & cracked
  • Repeated test for PVOH (H2SO4)
    • Air dry mass: 0.35714 g
  • Air dried for 2 days