Polymer problems
One of the useful The characteristics of something. In chemistry, chemical properties include the reactions a substance can take part in. Physical properties include colour and boiling point. of A large molecule formed from many identical smaller molecules known as monomers. is that they are A substance is unreactive or inert if it does not easily take part in chemical reactions.. This means they are suitable for storing food and other substances safely. Unfortunately, this property makes it difficult to dispose of polymers.
Not biodegradable
Most polymers, including poly(ethene) and poly(propene) are not Material that can be broken down in the environment by microorganisms.. This means that Microscopic living things such as archaea, bacteria and some species of eukaryotes. cannot break them down, so they:
- cause a litter problem if disposed of carelessly
- last for many years in Places where refuse is buried underground.
Suitable places for landfill sites are difficult to find. Space in landfill sites is wasted if it is filled with non-biodegradable polymers.
Question
Describe what 'biodegradable' means.
If something is biodegradable, it can be broken down or decomposed by microorganisms.
Combustion
Waste polymers can be Burned, particularly at a high heat.. This involves The process of burning by heat. at very high temperatures. Incineration releases a lot of The capacity of a system to do work or the quantity required for mechanical work to take place. Measured in joules (J). For example, a man transfers 100 J of energy when moving a wheelbarrow. which can be used to heat homes or to generate electricity.
There are problems with incineration:
- carbon dioxide is produced, a The gases responsible for global warming - carbon dioxide, methane, nitrous oxide and CFCs (chlorofluorocarbons). which contributes to The rise in the average temperature of the Earth's surface.
- Poisonous. gases are produced which need removing before they leave the chimney
Recycling
The use of landfill and incineration wastes valuable Anything that is useful to people. . Mixture of hydrocarbons, mainly alkanes, formed over millions of years from the remains of ancient dead marine organisms. is the raw material for making most polymers, and it is a A resource that is no longer being made or which is made extremely slowly, such as crude oil and metal ores.. Reusing materials or reprocessing waste materials to produce new materials. reduces the problems of disposal, and also reduces the volume of crude oil used.
Recycling involves:
- melting the waste polymer
- forming the polymer into a new product
However, different polymers must be separated from each other first. This can be difficult and expensive to do.
