Thermosoftening and Thermosetting Polymers

• What is the difference between thermosoftening and thermosetting polymers?


  Thermosoftening polymers melt when heated, while thermosetting polymers do not melt when heated
• What forms a polymer?


  A polymer forms by joining together a large number of monomers
• What is the monomer used to form polyethene?


  Ethene
• How do the properties of polymers depend on their formation?


  The properties depend on both the monomer and the conditions used to make the polymer
• What type of polymer is low density polyethene?


  A soft polymer
• What is the difference between low density and high density polyethene?


  Low density polyethene is soft, while high density polyethene is harder
• What conditions can be changed to alter the properties of a polymer?


  Reaction temperature, reaction pressure, or the catalyst
• What happens to thermosoftening polymers when heated?


  They melt and can be reshaped
• What occurs when thermosoftening polymers are cooled after melting?


  They reform intermolecular forces and return to a solid state
• How are the polymer chains in thermosoftening polymers held together?


  By intermolecular forces
• What is a key feature of thermosetting polymers?

  The polymer chains are connected by strong cross-links
• Why do thermosetting polymers not melt when heated?


  Because the strong cross-links are not broken by heat
• What are the properties of thermosoftening and thermosetting polymers?


  • Thermosoftening polymers:
  • Melt when heated
  • Can be reshaped
  • Return to solid when cooled
  • Thermosetting polymers:
  • Do not melt when heated
  • Have strong cross-links between chains
• What should you remember about the conditions for polymer formation in exams?

  • Specific conditions are not required
  • You may be asked to suggest a condition that could change properties