2. Addition Polymers Option C.3 By: LW433

3. What is a polymer??? A polymer is a molecule composed of repeating monomers which are usually connected by covalent bonds.

4. These are models of monomers When combined, they form a polymer

6. What does IB want us to know about Addition Polymers???

7. C.3.1 Describe and explain how the properties of polymers depend on their structural features.

8. Branching There are two ways of classifying a polymer by the number of branches it has. Low-density and High-density. Get it? It looks like a tree!

9. Low-Density Polyethene (LDPE) Polymerized at high temperatures Significant amount of branching Molecules are prevented from packing close together Flexible Melts at about 85 degrees Celsius

10. High-Density Polyethylene (HDPE) Polymerized at low temperatures Longer chains than LDPE Molecules are able to pack more closely together Melts at about 120 degrees Celsius Rigid shape

11. Another way to classify polymers is by the positions of their alkyl groups.

12. Think back to Organics… They were classified as being either “cis” or “trans”. “Cis” was when the molecules were on the same side. “Trans” was when the molecules were on opposite sides.

13. That same concept is applied to addition polymers!

14. Isotactic refers to when the alkyl groups are all on the same side of the polymer strand. Think “cis”.

15. Atactic refers to when the alkyl groups are on opposite sides of the polymer chain. Think “trans”.

16. C.3.2. Describe the ways of modifying the properties of addition polymers.

17. Plasticizers Small molecules that can fit between long polymer chains Weaken attraction between chains Polymers become more flexible Turn from rigid to completely pliable Example: Polyvinyl chloride

18. Volatile Hydrocarbons Add pentane during formation of polystyrene Heated in steam, the pentane vaporizes Expanded polystyrene is produced Light, good thermal material Used as packaging

19. ALMOST DONE YA’LL

20. C.3.3. Discuss the advantages and disadvantages of polymer use.

21. ADVANTAGES

22. Polymers can be customized by Strength Thermal and electrical insulation Flexibility Density Lack of reactivity

23. DISADVANTAGES 

24. Depletion of Natural Resources Most polymers are carbon based Carbon comes from oil and coal Both sources are limited

25. Disposal Lack of reactivity makes plastics not easy to dispose They can be burned, but if not done properly, poisonous dioxins are produced Hydrogen Cyanide and Hydrogen Chloride

26. Biodegradability Most plastics are not natural Are not degraded by organisms The anaerobic conditions of landfills make biodegradation very slow or cause it to stop.

27. That’s all folks! Good luck on the IB test!