2. TOPIC 13 Plastics

3. Aplastic is a substance which can be shaped or moulded. The The Raw Material for plastics is Crude Oil. Plastics Plastics are types of polymers.

4. Polymerisation Polymers are long chain molecules made up by many small individual building blocks,called Monomers, joining together. Polymers are long chain molecules made up by many small individual building blocks,called Monomers, joining together. Polymer Molecule Monomers

5. Addition Polymers -(CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 ) n - (ethene) CH 2 =CH 2 + CH 2 =CH 2 + CH 2 =CH 2 Examples: Polythene: Made from many ethene molecules joining together. For an Addition Polymer to be formed the monomers must have a C=C double bond. (Polythene)

6. Other examples of Monomers Polychloroethene (better known as PVC, polyvinyl chloride) Polychloroethene (better known as PVC, polyvinyl chloride) CH 2 =CHCl Polyphenylethene (polystyrene) Polytetrafluoroethene (PTFE) i.e. Teflon CF 2 =CF 2 CH 2 =CHC 6 H 5

7. Recycling Plastics Plastics can be difficult to Recycle. Plastics can be difficult to Recycle. Some plastics can be melted and reshaped, however others can’t. Some plastics can be melted and reshaped, however others can’t. Plastics are said to be Non-Biodegradable ie. They cannot be broken down by Bacteria in the soil. Plastics are said to be Non-Biodegradable ie. They cannot be broken down by Bacteria in the soil. Plastics can give off poisonous fumes such as CO, HCN and HCl when burned. Plastics can give off poisonous fumes such as CO, HCN and HCl when burned.

8. Effect of Heat on Polymers Polymers that soften on heating are called Thermoplastic. Examples are Polythene, PVC, polypropene etc. Polymers that soften on heating are called Thermoplastic. Examples are Polythene, PVC, polypropene etc. Some polymers are largely unaffected by heating / do not soften on heating. These are known as Thermosetting Polymers. Their Structure is such that they contain Cross- Links between the long polymer chains. Examples are Bakelite and Mica. Some polymers are largely unaffected by heating / do not soften on heating. These are known as Thermosetting Polymers. Their Structure is such that they contain Cross- Links between the long polymer chains. Examples are Bakelite and Mica.