Plastics (WJEC GCSE Chemistry: Combined Science)

• Polymers / plastics have the following general properties:
  • Flexible
  • Strong
  • Good thermal and electrical insulators
  • Resistant to corrosion
  • Low density
  • Do not rot
• The specific properties of plastics / polymers are used to make informed decisions about their uses
• For example, poly(vinylchloride) is a very good insulator so it is often used to insulate electrical wiring 
  • This can prevent electric shocks and overheating

Using polymers for electrical wiring

Poly(vinylchloride) is commonly used to insulate electrical wiring

• The properties of polythene that make it suitable for use in plastic shopping bags are:
  • Flexible
  • Low density 
  • Waterproof
  • Non-toxic 
  • Unreactive

Photo by Roberta Errani on Unsplash

Table of other plastics and their uses

Plastic	Use(s)
Poly(propene)	ropes, crates
Poly(vinylchloride)	drain pipes, window frames
Poly(tetrafluoroethene)	non-stick pans

Landfill waste disposal

• Landfill sites are not desirable because they take up valuable land 
• Since polymers are nonbiodegradable, micro-organisms such as decomposers cannot break them down
• Therefore, plastic items will not decompose for hundreds of years which causes landfill sites to fill rapidly

Incineration

• Polymers release a lot of heat energy when they burn
• However, incineration / burning of plastic is not a good solution to the waste issue as it produces the greenhouse gas carbon dioxide, which contributes to climate change
• Some polymers release toxic fumes when they burn
  • An example of this is poly(vinylchloride) which releases toxic hydrogen chloride gas when burned

Recycling

• Recycling plastic reduces the amount of water that goes to landfill sites or is burned
• It can also help to conserve crude oil reserves as less energy is required to recycle plastics than produce them
• This means that finite natural resources, such as crude oil and other fossil fuels, can be better managed as they are not being used:
  • As raw materials for plastics in the manufacture of plastics
  • To power the industrial processes to manufacture plastics