2a.3 - New materials and Polymers

Question 1

Why do smart materials have weird properties?

Answer 1

They behave differently depending on the condtions

Question 2

What is nitinol?

Answer 2

A memory shape alloy

Question 3

How does nitinol work? (2)

Answer 3

• When it’s cool you can bend it but if you bend it too far it will stay like that.
• If it is heated above a certain temperature it goes back to a remembered shape

Question 4

How big are nanoparticles?

Answer 4

1 - 100 nanometres across

Question 5

What is a fullerene? (3)

Answer 5

• Molecules of carbon, shaped like hollow balls or closed tubes
• They are arranged in hexagonal rings
• Different fullerenes contain different numbers of carbon atoms

Question 6

What can fullerenes be joined together to make?

Answer 6

Nanotubes

Question 7

What is a nanotube?

Answer 7

Fullerenes joined together

Question 8

How strong are Carbon nanotubes?

Answer 8

Very Strong

Question 9

What can nanomaterials be used to make? (4)

Answer 9

• Catalysts - huge surface are to volume ratio
• Sensors - To detect one type of molecule
• Building materials - Stronger and lighter
• New cosmetics - Don’t leave white marks

Question 10

What are weak polymers called?

Answer 10

Thermosoftening polymers

Question 11

What are the features of a thermosoftening polymer? (4)

Answer 11

• No cross-links
• Easily melted
• When cools hardens into a new shape
• Can be melted and remoulded many times

Question 12

What are strong polymers called?

Answer 12

Thermosetting polymers

Question 13

What are the features of thermosetting polymers? (4)

Answer 13

• Cross-links
• Solid structure
• Doesn’t soften when heated
• Strong,hard and ridgid

Question 14

What will affect the properties of polymers?

Answer 14

Starting materials and reacting conditions

Question 15

How is low density polyethene made?

Answer 15

Heating ethene to about 200C under high pressure

Question 16

How is high density polyethene made?

Answer 16

Made with a lower temperature and pressure (with a catalyst)