SC24

• Polymers are long molecules made from lots of repeating units called monomers.

  Lots of monomers join up to make a polymer in a polymerisation reaction

  • protein ---> amino acids
  • starch ---> glucose monomers
  • DNA ---> nucleotides
• Addition Polymerisation - formation of long chain molecules from a small molecule (alkene monomer) joining together with no other product
• Condensation Polymerisation - formation of long chain molecules joining together with a small molecule (water) released
• Polymerisation requires a high pressure and catalyst.

  Monomers are unsaturated molecules (double bond) while polymers are saturated (single bond)
• Polyesters form in a reaction between two monomer molecules:

  • one molecule containing two carboxylic acid groups
  • one molecule containing two alcohol groups

  When these two react together, an ester link is formed between one alcohol and one carboxylic acid group (water ejected as a by product).
• Many polymers are made from the products of carbon long hydrocarbon molecules so many are non-recyclable and non-biodegradable:

  • build up in landfill sites and take up valuable space
  • burnt to generate energy but contributes to climate change
• Some polymers can be recycled but they need to be separated before being melted down which is difficult
• Recycling Polymers:

  • can make profit as recycled materials are resold (advantage)
  • reduces space taken up in landfill sites (advantage)
  • conserves natural resources (advantage)
  • often have different strains which are difficult to recycle (disadvantage)
  • can act as an energy source (advantage)
  • versatility and strength reduces over time due to contamination (disadvantage)
  • lots of time and money spent (disadvantage)