Polymerisation

• Polymers are large, chain-like molecules that can extend for 1000s of atoms.
• Polymers are held together by:

  • Strong covalent bonds
  • Weak intermolecular forces

  However, due to their great size, these intermolecular forces add up to be quite strong.

  Therefore, polymers are usually solid at room temperature.
• Addition polymerisation

  The joining of short-chain monomers to form one long-chain polymer.
• What are the monomers in addition polymerisation?

  Alkenes, due to their C=C being able to open up to allow multiple alkenes to join together.
• What are the products of addition polymerisation?

  The polymer is the only product of this reaction.
• Monomer - A molecule that can be bonded to other identical molecules to form a polymer.

  Polymer - A substance of material made of many repeating units derived from one monomer.
• Naming addition polymers is easy. Simply add the prefix 'poly' followed by the monomer used.

  eg. monomer is ethene, polymer is poly(ethene).

  
• Condensation polymerisation

  The joining together of monomers with 2 functional groups to produce larger polymers, as well as a small by-product. (eg. H2O)
• Products of condensation polymerisation:

  • Large Polymer
  • Small by-product
• Amino acids are organic compounds that have 2 different functional groups:

  • Amine group (-NH2)
  • Carboxyl group (-COOH)
• Amino acids can be combined by condensation polymerisation. The products of this reaction are:

  • polypeptide
  • water
• The bond combining carboxyl groups with amine groups in amino acids are called peptide links, producing polypeptides.

  When 1 or more of these polypeptides become associated, a macromolecule called protein is formed.
• Most DNA molecules are made up of 2 polymer chains arranged in the form of a double-helix. The monomer used in these polymers is nucleotides.