2. Plastics n A n A plastic is a substance which can be shaped or moulded. n The n The Raw Material for plastics is Crude Oil. n Plastics n Plastics are types of polymers.

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

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

5. Other examples of Monomers nPnPnPnPolychloroethene.(better known as PVC,polyvinyl chloride). -CH2=CHCl- nPnPnPnPolytetrafluoroethene.(PTFE)ie Teflon -CF2=CF2- nPnPnPnPolyphenylethene.(polystyrene) -CH2=CHC6H5-

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

7. Effect of Heat on Polymers nPnPnPnPolymers that soften on heating and Harden when cooled are called Thermoplastic. Examples are Polythene, PVC, polypropene etc. nSnSnSnSome polymers are largely unaffected by 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.