1. Making Plastic from Protein
A plastic is made from casein, the protein in milk.
9/20/2018

2. Purpose
Using common household items such as milk and vinegar a complex polymer such as plastic can be made.
9/20/2018

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.
9/20/2018

4. Concepts
1. Biological Molecules
2. Denaturation
3. Polymers
9/20/2018

5. (Carbohydrates, Fats and Proteins)
9/20/2018
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
9/20/2018

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.
9/20/2018

7. 3. Polymers A=B ® A-B-A-B-A-B-A-B-A-B...........
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
A=B ® A-B-A-B-A-B-A-B-A-B
9/20/2018

8. Conclusion The casein was denatured by the vinegar.
The casein was extracted from the milk.
The rubbery casein’s protein molecules bound tightly together.
A hard plastic was made.
9/20/2018

9. 9/20/2018
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.
9/20/2018