Mr Oliver F334 - Material Revolution

Question 1

What is the word used to describe the reactvitiy of a polyalkenes carbon skeleton?

Answer 1

Intert

Question 2

True or false? Polyalkenes are biodegradable?

Answer 2

False

Question 3

What is a nylon?

Answer 3

A Polyamide

Question 4

Why are Polyamides soluble in water?

Answer 4

As they can hydrogen bond as a result of the Nitrogen atom with a lone pair of electrons

Question 5

Why do Polyamides get less soluble the bigger the alkyl group gets?

Answer 5

As this disrupts the hydrogen bonding in the water

Question 6

What is produced in condensation reactions, and is the atom economy 100%?

Answer 6

A small molecule such as HCl or H2O

No

Question 7

What are needed to form a nylon (Polyamide)?

Answer 7

Diamine + Dicarboxylic acid

Question 8

What is the formula of an acyl group?

Answer 8

C=OCl

Question 9

What is created when an amide link is broken by hydrolysis in alkaline conditions?

Answer 9

A carboxylate anion / salt

Question 10

What are the conditions needed to from a Polyester?

Answer 10

Concentrated Sulfuric acid

Heat under reflux

Question 11

What two molecules need to be reacted to form a Polyester?

Answer 11

Carboxylic acid and diols

Question 12

What must the solvent be in recrystallisation?

Answer 12

Soluble in warm tempretures

Insoluble in cold tempretures

Question 13

Describe how recrystallisation occurs

Answer 13

Select a solvent in which the solvent is soluble in warm tempretures, and is insoluble in cold tempretures
Dissolve the mixture in a minimum quantity of hot solvent
Filter the mixture to remove any insoluble impurities
Collect the formed crystals by vaccum filltration and wash them
Dry the crystals in an oven

Question 14

True or false? All apparatus in recrystallisation must be warm

Answer 14

True

Question 15

What, in terms of polymers, does crystalline and amorphous mean?

Answer 15

Crystalline = Ordered regions
Amorphous = Random regions

Question 16

Why do longer polymer chains mean stronger polymers?

Answer 16

As the more tangled they become
The more / stronger the intermolecular bonds are between the chains, and so the chains are less likely to slide over each other, so they are less flexible

Question 17

True of false? The more crystalline a polymer is, the stronger it is?

Answer 17

True

Question 18

What type of poly(ethene) have side branches?

Answer 18

Low density (LD)

Question 19

What conditions are needed to form high density poly(ethene)?

Answer 19

60 degrees, low pressure, TiCl3 catalyst

Question 20

What conditions are needed to form low density poly(ethene)?

Answer 20

200 degrees, 2000atm, no catalyst

Question 21

What is cold-drawing?

Answer 21

A way of increasing crystallinity by stretching polymers

This forms two necks at either side of the polymer

Question 22

What type of bond are made between chains of a thermosetting polymer?

Answer 22

Covalent

Question 23

Can thermosoftening polymers be reshaped / melted

Answer 23

Yes

Question 24

Define a glassy region

Answer 24

If a polymer is cooled to a low tempreture the amorphous regions becomes glassy, and becomes very brittle

Question 25

What is the glass transition tempreture (Tg)?

Answer 25

The point at which when a polymer (with glassy regions) is heated they will be able to move again relative to one another

Question 26

How can the Tg point be reduced?

Answer 26

Co-polymerising PVC (chloroethene) with small amounts of ethenyl ethanoate

Question 27

What is a plasticiser?

Answer 27

A molecular lubricant that sits between polymer chains, and forces the chains apart