Properties of Polymers

• Thermosetting polymers: Polymers that permanently become hard / rigid when heated (charred if heated too strongly)
• Thermosoftening polymers: Polymers that can soften and be reshaped when heated
• Why do thermosetting polymers harden when heated?

  It's covalent bonds crosslink, making it stronger when heated as cannot slide over each other
• Why do thermosoftening polymers soften when heated?

  The have weak intermolecular forces
• 2 types of poly(ethene):

  • Low-density poly(ethene)
  • High-density poly(ethene)
• What structure do low-density poly(ethene) have?

  Branched polymer chains
• What structure do high-density poly(ethene) have?

  Linear polymer chains