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Slide 1

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Plastics…read more

Slide 2

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Advantages of plastics over other
0 Lightweight Remember at
least 4 of these
0 Self coloured
0 Self finished
0 Thermal insulation
0 Electric insulation
0 More user friendly
0 More complex shapes can be manufactured…read more

Slide 3

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Where do plastics come from?
Animal or vegetable by products
Coal ­ Oil ­ Gas for purely synthetic plastics.
Made by "Thermal Cracking" process
Majority of plastic materials…read more

Slide 4

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There are 3 types of plastic materials:
0 Thermoplastics - can be repeatedly heated and moulded.
0 Thermosets ­ undergo a chemical change making them
permanently rigid & cannot be reheated and changed
0 Elastomers ­ have good elasticity, under pressure they
change shape but return to their original shape when the
pressure is removed
This is Paul lemur.
He is a lemur named Paul.…read more

Slide 5

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Game! The structure of plastic
Match `em up.
A tangle of long chain
Can be repeatedly molecules. The
Elastomers reheated and Epoxy resins molecules are held
remoulded together by strong
electrostatic forces.
Undergo a chemical Consist of long chain
change resulting in molecules and held
Thermosets Acrylic
them being together by rigid
permanently rigid cross links
Liquid silicone No molecular cross
Thermoplastics Have good elasticity
rubber links…read more

Slide 6

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Low Density Polyethylene
High Density Polyethylene
· HDPE has good · LDPE has low · Moderate
stiffness, good stiffness, and low chemical
chemical rigidity. It has resistance.
resistance and of good chemical · This is good for
course, its high resistance, making a wide
density. similar to HDPE. range of clothing.
· This is good for Of course, it is Also for electrical
crates, bottles, low density plugs and sockets.
buckets and (lightweight).
bowls. · These properties
are useful for
carrier bags, toys
and detergent
bottles.…read more

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