1. Engineering Materials: Chemistry, Pollution, and Solutions

2. Materials and Pollution
Materials engineers apply an understanding of chemistry and material science to design and manufacture new materials that are useful in everyday life.
In this unit we will learn about the chemistry and engineering of everyday materials:
polymers - all plastics, rubber, wool, cotton
composites - wood, paper, concrete, fiberglass, carbon-fiber materials
alloys - steel, aluminum cans, brass, bronze
glass - optical fibers

3. Pollution What happens when we are done with these materials?
some are recycled
some recyclable materials are thrown away and end up in landfills
much of the material ends up as pollution on land or in water

4. Monomers and Polymers
Monomers are small molecules that build up polymers
A polymer is a large complex ________ built from monomers joined together in a repeating pattern by a chemical bond.
A polymer’s chemical properties depend on the monomers that make them up.
Ex. of polymers: protein in meat, plastics, polyester, nylon.

5. Polymer Arrangements

6. Synthetic Polymers
Synthetic polymers are inexpensive to make, strong, and last a long time.
They do not break down into simpler substances like ______________ do. As a result, plastics build up in the environment in the form of trash.
A way to reduce the amount of trash is through _____________.
Recycled plastics can be used to make bottles, clothing and many other substances.
Ex: polystyrene, nylon, kevlar

7. Natural Polymers
Ex: Cellulose is a flexible and strong polymer found in fruits and vegetables.
It is also found in the cell walls of plants
When in long chains, humans cannot digest it
When it is connected in shorter chains, as in starches, humans can digest it
Other examples: Silk, wool, proteins in the body

8. Homework due tomorrow
On a sheet of lined paper, with the heading “Everyday Materials and Recycling”:
Make a list of four different things that you regularly throw out in your house or at school that you realize could be recycled.
How could you use engineering to improve your disposal of recyclable materials at home and at school?

9. Composites
A composite is made of two or more different polymers and has different properties than the polymers it is made of.
Ex: paper