Chapter 9-Polymers

Question 1

Define a polymer

Answer 1

A polymer is thousands of small units strung together in one large chain

Question 2

Define monomer

Answer 2

A single piece of a polymer

Question 3

How are monomers joined together?

Answer 3

Polymerisation

Question 4

Do polymers need to consist of all the same monomer?

Answer 4

No they can be different or they can be the same

Question 5

Define Co-polymers

Answer 5

Are formed when two or more different monomers are used

Question 6

Define thermoplastic polymers

Answer 6

Polymers that can be heated repeatedly and softened

Question 7

Define thermoset polymers

Answer 7

Do not soften, but char when heated, they do not reshape.

Question 8

What type of bonds do polymers require?

Answer 8

A double bond

Question 9

What are the two main ways of producing polymers?

Answer 9

Addition polymerisation

Condensation polymerisation

Question 10

What are two important polymers that are produced from ethene?

Answer 10

Low density polyethene

High density polyethene

Question 11

Explain low density polyethene

Answer 11

Polymer chains support a large number of branches
-The only forces are dispersn forces so the brances keep them apart, this attraction becomes weaker as the branches become further apart.

Question 12

Explain high density pressure polyethene

Answer 12

• Produced using low pressure

- Chains are very short and have very few side branches, which are held together by dispersion forces

Question 13

What are some propertes of low denisity poly ethene

Answer 13

-Soft and flexible

Question 14

What are some propertes of high denisity poly ethene

Answer 14

Ridgid and structured

Question 15

Define Isotactic in regards to polymers

Answer 15

When side branches are arranged on the same side of the linear polymer, polymers are packed close together resulting in a high density substance .

Question 16

Define atatic in regards to polymers

Answer 16

When branches occur at irregular points on both sides of the linear polymer.
Low density substance is formed.

Question 17

What does the prescence of cross-linking affect

Answer 17

Elasticity and rigidity of the polymer

Question 18

What does a small amount of cross linking produce?

Answer 18

An elastomer, realtively elastic

Question 19

What does a large amount of cross linking produce?

Answer 19

-Produces a ridgid polymer (thermoset)

Question 20

How does the degree of crystallinity affect the polymer?

Answer 20

More regions of regular arrangement increase strength

Question 21

How does the length of the polymer affect the polymer?

Answer 21

The longer the chain, the smaller the polymer

Question 22

How does the addition of plasticisers affect the polymer?

Answer 22

Plasticisers are small molecules in polymers to make them more flexible.

Question 23

Do thermoplastics have cross-linking

Answer 23

No

Question 24

Example of thermoplastic

Answer 24

Polystyrene

Question 25

Example of thermoset

Answer 25

Bakelite

Question 26

What are the only forces in polymer chains?

Answer 26

Dispersion forces

Question 27

What does the addition of plasticers actually do?

Answer 27

Cause the polymer chains to move slightly furhthur apart resulting a more softer and flexible polymer