14.3 - Addition Polymers

Question 1

Inert nature of addition polymers(3):

Answer 1

• unreactive due to lack of double bonds and non-polar structure
• only contain single covalent bonds - makes them saturated compounds with maximum stability
• also has a carbon backbone lacking any polar groups, giving an overall non-polar molecule

Question 2

Example of plasticisers (PVC):

Answer 2

• Unplasticised PVC has long, closely packed chains making it rigid but brittle.It is used in applications such as pipes, window frames, and floor coverings.
• Plasticised PVC has much greater flexibility, allowing uses like cable insulation, shower curtains, and clothing.

Question 3

What are plasticisers? Where do they position themselves and what does this do to the chains?

Answer 3

• small molecules that can be added to polymers to increase flexibility
• Plasticiser molecules position themselves between polymer chains.
• This pushes the chains apart, weakening VDW forces between polymer chains.
• The chains can now slide over each other more easily when bent.

Question 4

intermolecular strength difference between straight and branched polyalkenes

Answer 4

• longer straighter polyalkenes require more thermal energy to overcome as they contain stronger IMFs - makes them harder and rigid
• shorter/branched polyalkenes have weaker IMFs - makes them more flexible

Question 5

Deducing monomers from a polymer section

Answer 5

Identify the smallest section that repeats in the full polymer chain.
Replace the carbon-carbon single bond with a double bond.

Question 6

Drawing polymer repeating units:

Drawing polymer repeating units:

Answer 6

Replace the carbon-carbon double bond with a single bond.
Extend single bonds from each carbon atom to represent attachment sites within the polymer chain.

Question 7

Polymerisation of alkenes

Answer 7

• carbon double bond can open up - allows alkene molecules to join to end-to-end and form long chains called polymers
• alkenes are monomers
• polymers are formed from the monomers

Question 8

Physical properties of polyalkenes and influences (2)

Answer 8

1. Chain length -Longer chains allow more surface contact between neighbouring chains. This strengthens the intermolecular forces.
2. Branching - Straight chains can pack together closely in an ordered structure, maximising intermolecular forces. Highly branched chains cannot pack as efficiently, reducing contact between chains.

Question 9

Naming addition polymers:

Answer 9

1. Take the name of the alkene monomer.
2. Enclose the monomer name in brackets.
3. Add the prefix “poly”.