CIE A Level Chemistry复习笔记7.7.4 Predicting & Deducing the Type of Polymerisation

• When a set of monomers are given in an exam question, the type of polymerisation can be determined
• Firstly, it’s important to identify the key functional groups in the monomers

Addition polymerisation

• If the monomer/s contain a C=C double bond, they will polymerise through addition polymerisation
• The double bond can open up in order to add more monomers either side of the starting monomer
• This type of polymerisation makes (poly)alkenes

Addition polymerisation of one alkene monomer is polymerised, a (poly)alkene is formed

• (Poly)alkenes can be produced if there are 2 or more alkene monomers as well
• When more than one monomer is used for addition polymerisation, the resulting product is known as a copolymer

Two or more different alkene monomers can also be polymerised in Addition polymerisation. This gives a co-polymer

Condensation polymerisation

• Condensation polymerisation makes polyamides and polyesters
• When looking to identify this type of polymerisation, there are some key functional groups to be aware of

Monomers for condensation polymers table

• The type of polymerisation can be determined by considering the structure of the polymer backbone

Identifying addition polymerisation

• The polymer backbone of an addition polymer does not contain functional groups
• The backbone of the polymer is generally a chain of carbon atoms
• There may be sidechains branching off from the backbone
• Some examples of side chains are benzene rings, nitrile groups (-CN) and halogen atoms (-F/-Cl/-Br/-I)

Addition polymers are identified using the plain carbon chain as the polymer backbone

Identifying condensation polymerisation

• A condensation polymer can be identified by functional groups on the polymer backbone
• Polyesters contain ester links and polyamides contain amide/peptide link on the backbone itself

Condensation polymers are identified using function groups that form parts of the polymer backbone