polymers

• a polymer is a substance which has a molecular structure built up completely from a large number of similar units bonded together
• the intermolecular forces between polymer molecules are relatively strong and so these substances are solid at room temperature
• polymers are made by joining together thousands of small, reactive molecules called monomers. this reaction is called polymerisation
• polymers that are synthesised in a lab are called synthetic polymers. these are made from substances extracted from the earth's crust
• polymers fall into two categories:

  • thermosetting plastic or thermoset
  • thermoforming plastic or thermoplastic
• thermosetting polymers:

  • brittle
  • can be formed once
  • hard to recycle
  • good insulators
  • resistant to heat and chemicals
• thermoforming polymers:

  • can be heated
  • can be formed repeatedly
  • pliable
  • can be recycled