polymer usage and disposal

• polymers


  large compound formed from combinations of many monomers
• polymer repeating unit

  
• polymers are ... room temperature


  solid
• why are polymers solid at room temperature?

  because the intermolecular forces are strong, needing more energy to break them
• why do polymers have lower melting/boiling points than ionic/giant molecular compounds?

  because the intermolecular forces in polymers are weaker than ionic and covalent bondsSee an expert-written answer!We have an expert-written solution to this problem!
• plastics are made up of...

  long chain molecules called polymers
• polymerisation


  a chemical reaction joining monomers in long chains to form a polymer, which usually needs high pressure and a catalyst
• the monomers making up plastics are often...

  alkenes
• addition polymers are made from...

  unsaturated monomers with double covalent bonds
• addition polymerisation


  the process in which unsaturated alkene molecules (monomers) open up their double bonds and join together to form polymer chains
• monomer to polymer diagram

  
• polymer disposal
• LDPE


  low density polyethylene
• what is LDPE?


  polymers with chains relatively far apart (branches)
• LDPE uses


  plastic bags, sheeting and electrical cables
• what is HDPE?


  polymers with chains relatively close together (no branches)
• HDPE


  high density polyethylene
• HDPE uses


  plastic bottles, pipes, buckets
• LDPE vs HDPE

  
• thermosoftening polymer


  plastics which will soften when heated and can be reshaped
• why do thermosoftening polymers soften?

  thermosoftening plastics do not have crosslinks between neighbouring polymer molecules, so the molecules can move over each other when heated and the plastic melts as they are only tangled together
• thermosoftening polymer diagram

  
• thermosetting polymer


  plastics do not soften on heating, they are used when resistance to heat is important
• thermosetting polymer diagram

  
• why don't thermosetting polymers soften?

  the crosslinks in this thermosetting plastic are strong and prevent the plastic melting when it is heated
• crosslinks


  covalent bonds linking one polymer chain to another chain
• ways to get rid of polymers

  landfill, burning, recycling, monomer recovery
• ways to get rid of polymers: landfill advantages

  - low cost

  - easy
• ways to get rid of polymers: landfill disadvantages

  - resources cannot be reused

  - greenhouse gases emitted (from methane)

  - contributes to landfill waste

  - plastics take a long time to break down
• ways to get rid of polymers: burning advantages

  - generates electricity/heat

  - saves landfill waste
• ways to get rid of polymers: burning disadvantages

  - environmentally unfriendly due to toxic gases and carbon dioxide

  - resources cannot be reused
• ways to get rid of polymers: recycling advantages

  - resources may be reused

  - saves raw materials (e.g. crude oil)

  - environmentally friendly
• ways to get rid of polymers: recycling disadvantages

  - time consuming as they need to be recycled in the same types

  - air pollution from lorries transport

  - water pollution as they must be washed
• ways to get rid of polymers: monomer recovery advantages


  - resources can be reused
• ways to get rid of polymers: monomer recovery disadvantages

  - expensive

  - time consuming

  - hard to make the plastic you started with