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early experiments
samples
tensile
flexural
conductivity

Preparation of Samples

We prepared our samples by dissolving cellulose acetate fabric in acetone and then mixing in the reinforcement fibres. A major problem with our previous method of producing the samples was the fact that air bubbles became trapped as the acetone evaporated. In an attempt to solve this problem, we allowed the samples to dry under a vacuum. This, however, only exacerbated the problem, which likely means that formation of the air bubbles is due to the fact that the acetone evaporates too quickly from the mixture. To solve this problem, we allowed the acetone to evaporate more slowly by placing a lid on top of the Petri dish. This creates an area of acetone vapour above the surface of the sample.

Method

Proportions
For the control samples:

  • 40.0mL acetone
  • 2.00g cellulose acetate fabric

Reinforced: 5% fibre content by mass:
  • 40.0mL acetone
  • 1.90g cellulose acetate fabric
  • 0.10g reinforcement fibre

Reinforced: 25% fibre content by mass:
  • 40.0mL acetone
  • 1.50g cellulose acetate fabric
  • 0.50g reinforcement fibres

Reinforced: 45% fibre content by mass:
  • 40.0mL acetone
  • 1.10g cellulose acetate fabric
  • 0.90g reinforcement fibres

Procedure:
  1. Cut the cellulose acetate fabric into small pieces.
  2. Pour acetone into a 100mL beaker. Place a magnetic stirrer into the beaker, and cover the beaker with a Petri dish cover so that the acetone will not evaporate from the beaker.
  3. Set the magnetic stirrer on medium speed.
  4. Lift the cover quickly and add a few pieces of the CA fabric. Replace cover.
  5. When the CA has completely dissolved in the acetone, add a few more pieces. Allow the CA to dissolve completely after each addition before adding more CA. Continue until all the CA has been dissolved in the acetone.
  6. For the fibre reinforced samples, slowly add the fibres until they are distributed evenly throughout the mixture.
  7. Remove the stirring rod. Pour the mixture into a Petri dish and quickly cover with Petri dish cover.
  8. Allow 48 hours for the mixture to dry. A thin piece of plastic will form, which can be easily popped out of the Petri dish.

Photographs of our samples

CA dissolved in acetone as it is being stirred by the magnetic stirrer

Control sample as it dries in the Petri dish

Hemp and flax reinforced samples as it dries in the Petri dish. The darker coloured ones are hemp and the lighter colored ones are flax.