Properties of Ceramics, Polymers and Composites

The three materials we will cover are ceramics, polymers and composites.

Ceramics

Ceramics are made by moulding material. Once the material has been moulded and shaped, it is then baked in an oven.

Two known types of ceramic materials are bricks and pottery.

Bricks are formed by baking moulded clay.

Pottery is also made by moulding clay, which used to make things like plates.

Properties of ceramics:

  • Very hard – This makes them useful as building materials
  • Do not conduct electricity
  • High melting points – They are great for storing hot liquids
  • Brittle – They are likely to break/shatter under pressure

Polymers

Polymers are long molecules that are made by joining many small molecules together, through chemical reaction, to make a long molecule.

For example, polyethene is a polymer which is made by joining many ethene molecules together.

The arrangement of atoms that form ethene are repeated over and over. For example, chloroethene below:

Chloroethene molecules join together to form longer molecules, called poly(chloroethene). The individual chloroethene molecules are joining together to form a polymer.

Natural Polymers

The polymers that occur naturally are called natural polymers.

For example wool

  • Wool is natural polymer which is produced from sheep

Another example is cotton

Cotton is a natural polymer produced by cotton plants

Synthetic Polymers

Synthetic polymers are man made polymers

Crude oil can be used in oil refineries to make different types of plastic polymers using chemical reactions.

Here are some examples of plastic polymers:

Plastic polymer Common uses
Low density poly(ethene) – LDPE Plastic bags
High density poly(ethene) – HDPE Harder plastics, such as bottles and toys
Poly(vinyl chloride) – PVC Water pipes and electronics

Properties of Polymers:

  • Solid at room temperature
  • Electrical insulators (they do not conduct electricity) – Which means you can hold wires without getting an electric shock
  • Strong – This c an be useful for plastic bags, which means they do not break easily.
  • Chemically unreactive – This means they can be used as bottles or containers, to store things such as food and water – However, there is a problem with polymers being unreactive. This means that they do not break down very quickly and so can cause issues in the landfill.

Remember polymers and their uses!

Polymer name Common use
Nylon Clothes
PVC Water pipes and coating of electrical wires
poly(ethene) Plastic bags
Lycra Clothing usually sports clothing

Composites

These are materials that are made from different types of materials. They are very useful because they combine two or more materials which have unique properties.

For example, if you like the properties of one type of material and you like the properties of another type of material, you can combine them to form a composite. This composite will have the properties of both materials.

An example of a composite is reinforced concrete, which is a mixture of both concrete and steel.

The two main properties of reinforced concrete:

  • Strong when compressed – because of the concrete
  • Strong when stretched – because of the steel

As reinforced steel contains both of these properties, it is a very strong material that can be used for many types of buildings.