1. KThumath Chemistry Saint Paul's
Plastics
KT7448A
27/05/2019
KThumath Chemistry Saint Paul's

2. KThumath Chemistry Saint Paul's
Introduction
Plastics are long chain molecules made from small “monomer” units that have been joined together
The process of making a plastic is called Polymerisation
27/05/2019
KThumath Chemistry Saint Paul's

3. KThumath Chemistry Saint Paul's
Topics of Discussion
Addition Polymers are made from small unsaturated molecules.
The C to C double bond opens up
The carbons then bond with the next carbon atom
Polymers are formed when thousands of small molecules join
27/05/2019
KThumath Chemistry Saint Paul's

4. KThumath Chemistry Saint Paul's
Good points
Advantages of Synthetic Polymers
They are cheap to make
They do not corrode
We can vary their properties
27/05/2019
KThumath Chemistry Saint Paul's

5. KThumath Chemistry Saint Paul's
More info
Disadvantages of Polymers
They are not biodegradable
They are made from crude oil which is finite
They give off toxins when they burn
Uses of Polymers
Poly(ethene) – bags
Poly(tetraflouroethene)- frying pans
Poly(vinylchloride)- cups, foam
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KThumath Chemistry Saint Paul's

6. KThumath Chemistry Saint Paul's
Toxins
When all plastics burn they release
Carbon monoxide
PVC – Hydrogen chloride
Poly(ethene) –Carbon monoxide
Nylon – Nitrogen
Polyurethane foam – Hydrogen Cynanide.
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KThumath Chemistry Saint Paul's

7. KThumath Chemistry Saint Paul's
Natural Polymers
Proteins - are made of thousands of small amino acid molecules
Carbohydrates – are made from thousands of sugar molecules.
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KThumath Chemistry Saint Paul's

8. KThumath Chemistry Saint Paul's
Addition Polymers
Made when small unsaturated molecules join.
The double bond opens up.
H H H H H H
I I I I I I
C=C + C=C + C=C ( monomers)
I I I I I I
H H H H H H
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KThumath Chemistry Saint Paul's

9. KThumath Chemistry Saint Paul's
Part of the polymer
H H H H H H
I I I I I I
- C – C – C – C – C – C –
I I I I I I
H H H H H H
CH2CH2 – REPEATING UNIT
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KThumath Chemistry Saint Paul's

10. Condensation Polymers
When two monomers join water molecules are released.
Proteins and Carbohydrates are condensation polymers.
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KThumath Chemistry Saint Paul's

11. KThumath Chemistry Saint Paul's
Example
Starch is made when many small glucose monomers join.
HO – * – OH +HO –*– OH+HO –*- OH
( * = glucose molecule)
HO - * - O - * - O - * - OH + 2 H2O
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KThumath Chemistry Saint Paul's

12. Thermosetting and Thermoplastics
Thermoplastics can be reshaped when heated. ( most addition polymers)
Thermosetting plastics crack on heating
27/05/2019
KThumath Chemistry Saint Paul's