DF7 - Addition polymerisation and co-polymerisation Flashcards
What is a polymer?
A long molecule made up of monomers
What is addition polymerisation?
When many polymers are formed in a reaction known as addition polymerisation
Give an example of an A-A polymer that is widely used
PVC (or also poly(ethene) & poly(chloroethene))
Give an example of an A-B polymer
Polyester (or also polyamides AKA nylons)
How can the repeated polymer structure be represented?
Using square brackets around the repeated unit with an ‘n’ on the outside of the brackets in subscript
What is copolymerisation?
When more than one type of monomer is used in an addition reaction
What is produced when you add hydrogen to C=C bonds?
Alkanes
What conditions are needed to react ethene with hydrogen to produce ethane? (There are two ways but name at least one)
- Use a nickel catalyst + a temperature of 150 degrees & a high pressure
OR - Use platinum catalyst at room temp. & pressure
How do you test for C=C bonds? What is the test also an example of?
Use bromine water - turns from orange to colourless (the Br water is used to test for unsaturation)
It is also an electrophilic addition reaction
Describe electrophilic addition reactions
- Double bonds open up + atoms are added to the C atoms
- Electrophilic addition reactions happen as the double bond has plenty of electrons + is easily attacked by electrophiles
- The double bond is nucleophilic - attracted to places that don’t have enough electrons
What is formed when hydrogen halides react with alkenes?
Haloalkanes (halogenoalkanes)
In what cases can there be two possible products in an electrophilic addition reaction?
When a hydrogen halide is added to an unsymmetrical alkene (e.g when propene + HBr react they produce
2-bromopropane + 1-bromopropane
