Polymers (AQA GCSE Chemistry)

• Polymers are large molecules of high relative molecular mass and are made by linking together large numbers of smaller molecules called monomers
• Each monomer is a repeat unit and is connected to the adjacent units via strong covalent bonds
• The intermolecular forces acting in between polymer chains are larger than those in between simple molecules so polymers are usually solid at room temperature
  • Examples of polymers include polythene and polychloroethene, commonly known as PVC

• Many everyday materials such as resins, plastics, polystyrene cups, nylon etc. are polymers
• These are manufactured and are called synthetic polymers
• Nature also produces polymers which are called natural or biological polymers
  • Examples include DNA, proteins, silk and wool

Polymers are made from very long carbon chains with a repeating unit

• Polymers are represented using a specific notation which is shown below using polythene as an example
  • You can spell it polythene or polyethene - both are acceptable

• The bonds on either side of the polymer must extend outside the brackets (these are called extension or continuation bonds)
• A small subscript n is written on the bottom right hand side to indicate a large number of repeat units

The simplest of all polymers is polyethene

• The relationship between the monomer, repeating unit and polymer is illustrated in this second example using polychloroethene
• Notice that the chlorines do not necessarily have to be drawn 'up' or 'down' from the chain, as long as every carbon has the correct atoms attached

The structure of polychloroethene and its monomer