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 dried for 2 days
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Project 1 & 2: Film Preparations & Characterizations
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