1. Section 3 – pg 306 Polymers and Composites
Chapter 8
Section 3 – pg 306
Polymers and Composites

2. Carbon’s Chains and Rings
Pg 306
Carbon’s Chains and Rings
Bonded carbons form the “backbones” to which other atoms attach

3. Carbon Compounds and Polymers
Pg 307
Carbon Compounds and Polymers
Polymers form when chemical bonds link large numbers of monomers in a repeating pattern
A polymer may consist of hundreds or even thousands of monomers

4. Pg 308
Natural Polymers
Cellulose: strong flexible polymer found in plant cell walls
Made in plants when sugar molecules are joined into long strands
Humans cannot digest cellulose
Starches: formed from sugar molecules that are connected in a different way than cellulose
Found in pastas, breads, and many veggies
Humans can digest starch

5. Polymers made by animals
Silk: fibers of the cocoons spun by silkworms
Wool: made from sheep’s wool
Protein: a polymer is made of the amino acid monomers
Depending on how they are used and in what order they form different things like fingernails, muscles and hemoglobin
Pg 308

6. Pg 309
Synthetic Polymers
Many common polymers are synthesized or made from simpler materials
The base for many is coal or oil
Plastic, carpet, clothing, glue, chewing gum are synthetic polymers

7. Pg 310
Comparing Polymers
Synthetic polymers are often used in place of natural materials that are too expensive or wear out too quickly
Polyester and nylon are used in place of wool, silk and cotton in clothes
Laminated countertops and vinyl floors replace wood
Synthetic polymers are also in CDs, computer parts, artificial heart valves and bike tires

8. Pg 310
Composites
Composite: combination of two or more substances in a new material with different properties
The combining of substances allows for a better stronger material to be made
Many composites include one or more polymers
A common natural composite is wood
Made of long fibers of cellulose held together by lignin
Cellulose is flexible but weak and lignin is brittle, but the combination of these two polymers makes wood strong

9. Pg 312
Uses of Composites
Fiberglass composites are composed of glass fibers woven together and strengthened with a liquid plastic
Strong and easy to mold material that is used for boat hulls, snow boards and bath tubs
Fiberglass will not rust like metal does

10. Pg 313
Recycling Plastics
It is often cheaper to throw plastics away and make new ones than it is to reuse them
This leads to increased volume of trash
Plastics last so long b/c they do not react very easily with other substances so they do not break down or degrade
You can help reduce the amount of plastic waste by recycling

11. Chapter 8 section 3 Homework – pg 313

12. 1A. What are polymers made of?

13. 1B. What properties enable carbon atoms to form polymers and so many other compounds?

14. 1C. How do the two kinds of polymers modeled in Figure 16 differ?

15. 2A. Distinguish between natural polymers, synthetic polymers, and composites.

16. 2B. Make a list of polymers you can find in your home
2B. Make a list of polymers you can find in your home. Classify them as natural or sythetic.

17. 2C. Why are composites often more useful than the individual materials from which they are made?

18. 3A. List two benefits and two problems associated with the use of synthetic polymers

19. 3B. What happens to waste plastics when they are recycled?

20. 3C. Think of something plastic that you have used today
3C. Think of something plastic that you have used today. Is there some other material that would be better than plastic for this use?