Problems with Polymers (Edexcel GCSE Chemistry)

Problems with Polymers

• Polymers are formed by the joining up of many small molecules with strong covalent bonds

• This makes polymers unreactive and chemically inert so they don’t easily biodegrade

Disposal of polymers is an environmental problem

Landfills

• Waste polymers are disposed of in landfill sites but this takes up valuable land, as polymers are non-biodegradable so micro-organisms such as decomposers cannot break them down

• This causes sites to quickly fill up

Incineration

• Polymers release a lot of heat energy when they burn and produces carbon dioxide which is a greenhouse gas that contributes to climate change

• Polymers that contain chlorine such as PVC release toxic hydrogen chloride gas when burned

• If incinerated by incomplete combustion, carbon monoxide will be produced which is a toxic gas

Recycling

• Polymers can be recycled but different polymers must be separated from each other

• This process is difficult and expensive

Recycling Polymers

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

Diagram showing the categories into which they must be sorted before recycling