Polymers

Question 1

What are plastics made from?

Answer 1

Lots of molecules joined together in long chains

Question 2

What determines the properties of plastics?

Answer 2

The forces between molecules

Question 3

Strong [ ] bonds hold the [ ] together in long chains. But It’s the bonds between the different [ ] chains that determine the [ ]

Answer 3

covalent
atoms
molecule
properties

Question 4

Describe what happens when there are weak intermolecular forces

Answer 4

Individual tangled chains of polymers, held together by weak intermolecular forces, are free to slide over each other.

Question 5

Describe the properties of Thermosoftening Polymers

Answer 5

Weak Intermolecular forces
Don’t have cross links between chains
Forces between the chains are really easy to overcome, so it’s easy to melt the plastic
When it cools, the polymer hardens into a new shape
You can melt and remould the plastic as many times as you like
(looks like spaghetti)

Question 6

Describe what happens when there are strong intermolecular forces

Answer 6

Some plastics have strong intermolecular forces between the polymer chains, called crosslinks, they hold the chain firmly together

Question 7

Describe the properties of Thermosetting Polymers

Answer 7

strong intermolecular forces
Crosslinks - These hold the chains together in a solid structure
The polymer doesn’t soften when it’s heated
Strong, hard and rigid
(Looks like wavy lines of bricks)

Question 8

What also affects the properties of plastics (Not forces)?

Answer 8

Starting materials and reaction conditions

Question 9

How is Low density (LD) polythene made?

Name a property and a use

Answer 9

Made by heating up ethene to about 200ᵒC under high pressure.
It’s flexible and is used for bags and bottles

Question 10

How is High density (HD) polythene made?

Name a property and a use

Answer 10

Made at lower temps. and pressure (with a catalyst).

More rigid and is used for water tanks and drainpipes