Plastics & the Environment

Specification Point 9.23C:
  • Describe some problems associated with polymers including the:
    a) availability of starting materials
    b) persistence in landfill sites, due to non-biodegradability
    c) gases produced during disposal by combustion
    d) requirement to sort polymers so that they can be melted and reformed into a new product

 Starting Materials

  • The main raw ingredient in the manufacture of polymers comes from crude oil.
  • This is a finite source and will eventually run out, with prices increasing as levels of production begin to fall.
  • Other products come from crude oil such as the raw materials for bulk chemicals, oil and fuels.
  • There will come a time when there will be competing interests over whether the raw materials from crude oil should be destined to the production of polymers or other products.

Non-biodegradability

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

Disposal by Combustion

  • Polymers release a lot of heat energy when incinerated and produce carbon dioxide which is a Greenhouse gas that contributes to climate change. 
  • If incomplete combustion occurs during the process, carbon monoxide will be produced. This is a toxic gas that reduces the capacity of the blood to carry oxygen.

Sorting and Recycling

  • Polymers can be recycled but different polymers must be separated from each other  and sorted into 7 different categories before recycling can take place.
  • This is a difficult and time-consuming process which also incurs extra expense.

Polymer Types, Edexcel GCSE Chemistry

Diagram showing the 7 categories and common uses of polymers into which they must be sorted before recycling

Recycling Polymers

Specification Point 9.24C:
  • Evaluate the advantages and disadvantages of recycling polymers, including economic implications, availability of starting materials and environmental impact

Advantages

  • Recycling is a more economically viable process than manufacturing from scratch.
  • It decreases the use of crude oil which allows it to be kept for other purposes.
  • It is better for the environment as plastic waste is being collected and reused, hence recycling reduces the emissions of Greenhouse gases and other toxic gases produced during the manufacturing process.
  • It also reduces the amount of landfill sites needed.
  • Recycling is itself an entire industry which creates employment and economic growth.

Disadvantages

  • Sorting plastics by type of polymer is a tedious and labour intensive process which is costly.
  • Recycling counts on what is collected in as the raw material, therefore production of certain types of polymers may not be possible due to a lack of starting ingredients.
  • Melting polymers produces toxic gases that are harmful to plants and animals.
  • Polymers can only be recycled a number of times before they lose their properties and become useless.
  • Recycling runs the risk of mixing different polymers together, which again will affect their properties. This is particularly risky for polymers designed for specialist use such as aircraft or automobile parts, where safety is of utmost importance.

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Edexcel GCSE Chemistry Notes

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Morgan Curtin Chemistry

Author: Morgan

Morgan’s passion for the Periodic Table begun on his 10th birthday when he received his first Chemistry set. After studying the subject at university he went on to become a fully fledged Chemistry teacher, and now works in an international school in Madrid! In his spare time he helps create our fantastic resources to help you ace your exams.