Transcript Plastics - Calderglen High School

TOPIC 13
Plastics
Plastics



A plastic is a substance
which can be shaped or
moulded.
The Raw Material for
plastics is Crude Oil.
Plastics are types of
polymers.
Polymerisation

Polymers are long chain molecules made up by
many small individual building blocks,called
Monomers, joining together.
Monomers
Polymer Molecule
Addition Polymers
For an Addition Polymer to be formed the
monomers must have a C=C double bond.
Examples:
Polythene: Made from many ethene molecules joining together.
CH2=CH2 + CH2=CH2+ CH2=CH2
(ethene)
-(CH2-CH2-CH2-CH2-CH2-CH2)n- (Polythene)
Other examples of Monomers

Polychloroethene (better known as PVC,
polyvinyl chloride)
CH2=CHCl
Polytetrafluoroethene (PTFE) i.e. Teflon
CF2=CF2
Polyphenylethene (polystyrene)
CH2=CHC6H5
Recycling Plastics




Plastics can be difficult to Recycle.
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 can give off poisonous fumes such as
CO, HCN and HCl when burned.
Effect of Heat on Polymers


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 CrossLinks between the long polymer chains.
Examples are Bakelite and Mica.