Film Casting

Formulation and method:

Heat 7g absolute ethanol (70 °C), add 1.6g (90%w/w) protein, stir until dissolved. Add 2g distilled water, stir, then add 0.6g plasticizer mixture (1 PEG: 1 glycerol: 1 lactic acid), stir for a further 4 minutes (makes 2 films).

Method of casting:

4g casting solution is placed in a petri dish and left overnight on a level surface to set.

Final film weight = approx 0.8g.

Film Quality Attributes

Tensile properties

Water Vapour Transmission

Tensile properties

• Measure force at break

• Calculate stress

• Measure extended distance at break

• Calculate strain

• Plot stress against strain

Zein 95

Zein 70

Water Vapour Transmission

• Measure water loss (g) through film with time over a period of 5 days (no control of temperature and Relative Humidity)

• Calculate Water Vapour Transmission

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0 10 20 30 40 50Time (h)

Wat

er lo

ss (g

) PE

Zein95

Zein70

Kafirin