Plastics and Their Disposal

• Synthetic polymers are ones made in a factory

  • e.g. nylon, terylene and lycra
• Nylon is a polyamide used to produce clothing, fabrics, nets and ropes
• PET aka Terylene is a polyester made from monomers which are joined together by ester links

  • PET is used extensively in the textile industry and is often mixed with cotton to produce clothing
• Uses of plastic

  A) plastic bags

  B) low

  C) density

  D) plastic bottles

  E) high

  F) density

  G) food packaging

  H) ropes

  I) carpets

  J) plastic sheets

  K) artificial leather

  L) drain pipes and gutters

  M) insulation on wires

  
• Non-biodegradable plastics - plastics which do not degrade over time or take a very long time to degrade, and cause significant pollution problems
• Plastic waste has been spilling over into the seas and oceans and is causing huge disruptions to marine life
• In landfills, polymers take up valuable space as they are non-biodegradable so microorganisms cannot break them down.

  • causes the landfill sites to quickly fill up
• Polymers release a lot of heat energy when incinerated and produce carbon dioxide which is a greenhouse gas that contributes to climate change

  • If incinerated by incomplete combustion, carbon monoxide will be produced which is a toxic gas that reduces the capacity of the blood to carry oxygen
• Polymers can be recycled but different polymers must be separated from each other which is a difficult and expensive process
• PET stands for polyethylene terephthalate

  • a common polymer used to make things like plastic bottles
• PET is a condensation polymer consisting of repeating ester units, so it is type of polyester, like terylene
• One of the problems with recycling polymers is that the condition needed to break them down

  • usually high temperatures and pressures can degrade the monomers making them unusable for re-polymerisation
• PET is relatively easy to convert back into the monomers

  • It can be depolymerised either using enzymes or by chemical methods
  • Enzymes present in microbes breakdown the PET into the original monomers
  • The same can be achieved using solvents a catalyst and mild heating
• Breakdown of PET

  • The monomers are recovered and be be polymerised into new PET
  • This saves on resources and energy, reducing the carbon footprint of the production process
• Breakdown of PET

  A) microbial

  B) enzymes

  C) 200 C

  D) catalyst

  E) dicarboxylic

  F) diol

  G) condensation polymerisation

  H) ester link

  I) repeating unit

  J) polyester

  K) heat

  L) catalyst

  
• PET can be converted back into monomers and re-polymerised
• PET bottle qualities

  • transparent
  • infinitely recyclable
  • can be capped and sealed
  • less greenhouse gas emissions
  • produces less product waste
  • are sent back to reclaimers
• When a carboxylic acid reacts with an amine, an amide is formed

  • water is released as the molecules joined together
• If a dicarboxylic acid reacts with a diamine, a polymer called a polyamide is formed and water is released
• Formation of amides

  A) groups of atoms

  B) functional groups

  C) small

  D) molecules

  E) monomers

  F) water

  G) join

  H) long

  I) chain molecule

  J) polymer

  K) repeating unit

  L) polymer

  
• Uses of nylon:

  • clothing
  • strings
  • rackets
  • fabric
  • parachute strings
• Most plastics aren’t recyclable and don’t biodegrade

  • can break down into small fragments aka microplastics
• Environmental challenges from plastics

  • Landfill gets filled up
  • Enters water supplies
  • Puts out toxic gases when burned
• What are the problems with plastic?

  expensive to recycle, aren't biodegradable, requires landfill sites, dangerous chemicals released during combustion, difficult to recycle
• Describe one environmental problem with non-biodegradable plastic

  getting stuck in gullets of birds