Making Plastic from Protein

1
Making Plastic from Protein

• A plastic is made from casein, the protein in
  milk.

2
Purpose

• Using common household items such as milk and
  vinegar a complex polymer such as plastic can be
  made.

3
Demonstration

• Milk was heated to almost boiling and vinegar was
  added.
• Rubbery material(casein) was drawn off and
  pressed into mold.
• The casein hardened over time and formed a
  plastic.

4
Concepts

• 1. Biological Molecules
• 2. Denaturation
• 3. Polymers

5
1. Biological Molecules
(Carbohydrates, Fats and Proteins)

• Carbohydrates consist of carbon, hydrogen and
  oxygen.
• often sugars and starches
• Milk sugar - Lactose
• Fats consist of carbon, hydrogen and oxygen.
• built up in plants and animals
• Milk fats - stearic acid - oleic acid
• Proteins contain carbon, hydrogen, oxygen and
  nitrogen.
• occur in all living matter
• building blocks of life
• Milk protein - casein - albumin

6
2. Denaturation

• Proteins have definite shapes and structures
• Altered shape Denaturation Loss of
  biological activity
• High temperature
• Cooking an egg
• Strong acids and bases
• Vinegar Milk
• The vinegar caused the protein (casein) in the
  milk to coagulate.
• The casein changed shape from a liquid to a
  rubbery solid.
• Altered shape Denaturation Loss of
  biological activity

7
3. Polymers

• Some polymers occur naturally, but the vast
  majority of polymers are man made.
• Polymers are long chains of the same small
  molecule repeated over and over.
• These long chains get tangled up like spaghetti.
• It is the way they get tangled up that gives
  plastic its strength.
• If the strands are held rigidly together, the
  result is a stiff plastic like casein.
• ornaments

AB A-B-A-B-A-B-A-B-A-B...........
8
Conclusion

• The casein was denatured by the vinegar.
• The casein was extracted from the milk.
• The rubbery caseins protein molecules bound
  tightly together.
• A hard plastic was made.

9
Comments
There are now thousands of plastics and polymers
and new ones are being made for everything from
sports clothes to spacecraft.
Plastics are so strong, light and unaffected by
corrosion that they are used in virtually
everything from light aircraft to artificial hips.