1. Addition Polymerisation Condensation Polymerisation Uses of polymers

2. Addition Polymerisation
A carbon – carbon double bond is needed in the monomer
A monomer is the small molecule that makes up the polymer

3. Addition Polymerisation
The polymer is the only product
Involves the opening out of a double bond
The conditions of the reaction can alter the properties of the polymer
Reaction proceeds by a free radical mechanism
Oxygen often used as the initiator

4. Addition polymerisation
The board specifies that you know this addition polymerisation reaction

5. Addition polymerisation
Conditions are high pressure and an oxygen initiator (to provide the initial free radical).
Monomer = phenylethene
Polymer = poly(phenylethene)

6. Addition Polymerisation
You are expected to be able to do the following things with addition polymers:
Predict the repeating unit of the polymer given the monomer
Predict the monomer from the polymer – displayed formula and even empirical formula.
Know about stereochemistry of addition polymers.

7. Prediction the repeating unit
This is easy, basically open out the double bond.

8. Predicting the monomer from the polymer
This is kind of the opposite to what you have just done.
They may ask you to draw different formulae.
You need to make sure you can convert repeating units into monomers, and draw a ring around the repeating unit

9. Stereoisomerism in Addition polymers.
Ziegla and Natta in the 1950s cam up with a way of controlling the repeating unit.
They won a Joint Nobel prize for their work
The polymerisation process can be controlled used a tin/aluminium catalyst at 50°C and 1.5atm

10. Stereoisomerism in Addition polymers.
Previous to this only one type of poly(ethene) could be made, called LDPE or low density poly(ethane).
The chains formed a tangled mass.
HDPE could now be produced.
This has a much stiffer structure due to areas of crytallinity where the polymer chains are much more ordered.

11. Stereoisomerism in Addition polymers.
HDPE has a much higher boiling point due to these more ordered regions.
Generally used to make plastic bottles.
Ziegler and Natta also discovered that they could make stereo regular polymers. Isotactic, syndiotactic and atactic.

12. Poly(propene) and stereoisomerism
Isotactic. This is a very regular type of polymer chain. All the methyl groups are on the same side.

13. Poly(propene) and stereoisomerism
Syndiotactic. A slightly less regular but still very ordered polymer.
The methyl groups alternate the side of chain they are on.

14. Poly(propene) and stereoisomerism
Atactic.
This is a completely random allocation of methyl groups along the carbon skeleton.

15. Poly(propene) and stereoisomerism
This varying degree of randomness will affect the strength and melting point of the polymer.
The less random, the stronger the polymer and the higher the melting point
This is because in a more ordered polymer they chains can get closer together and hence the van der Waal’s forces will be greater.

16. Condensation Polymers
Involves 2 monomers that have different functional groups.
They also involve the elimination of water or another small molecule.
Hence the term condensation polymer.
Monomer A + Monomer B  Polymer + small molecule (normally water).
Common condensation polymers include polyesters (the ester linkage) and polyamides (the amide linkage as in proteins).

17. Polyesters
The OCR example here is terylene, a polymer of benzene-1,4-dicarboxylic acid and ethane-1,2-diol.
The ester linkage is formed between the monomers

18. Polyesters
You need to be able to reproduce the formation of terylene, and possibly predict the structures of other polyesters

19. Polyamides
These involve the linkage of two monomers through the amide linkage as in proteins (e.g. silk)

20. Nylon 6,6 a polyamide

21. Kevlar a polyamide

22. Uses of polyamides
The main use of polyesters and polyamides is as fibres in clothing.
Most clothing now has a degree of manufactured fibres woven into the natural material (such as cotton).
This gives the material more desirable characteristics, such as stretchiness, and better washability.
Don’t forget that proteins are also polyamides, you must know how the linkage works with natural polymers such as proteins.