AS- Polymerisation of Alkenes

Specification reference 4.1.3 POLYMERISATION IN ALKENES

Polymers are extremely large molecules formed from many thousands of repeat units of smaller molecules known monomers.

Unsaturated Alkene monomers undergo addition polymerisation, to produce long saturated chains containing no double bonds. Properties of the polymers depends on the monomer used. Industrial polymerisation is carried out at high temperatures and high pressure using catalysts.

- Addition polymers have molecular masses.

- Synthetic polymers are usually named after the monomer that reacts to form their giant molecules, prefixed by 'poly'.

- A repeat unit is the specific arrangement of atoms in the polymer molecule that repeats over and over again.

General equation for polymerisation of any alkene^ 

- The 'n' after the bracket shows that there is a large number of repeats. 

Some polymers and monomers

Every day name: POLYETHENE                  Uses: Plastic bags

Everyday name: POLYPROPLYLENE        Uses: Crates, Ropes

Everyday name: POLYSTYRENE          Uses: Packaging foam 

Everyday name: PVC                                 Uses: Window frames

Everday name: PTFE/Teflon              …