Plastics (WJEC GCSE Chemistry)

Properties & Uses of Plastics

• 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

Environmental Issues of Plastics

Many polymers are chemically unreactive which means that they are nonbiodegradable This means that the disposal of plastics can cause environmental issues

Photo by Katie Rodriguez on Unsplash

• The three main methods to dispose of plastics are:

  • Landfill waste disposal

  • Incineration / burning

  • Recycling

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