Properties of Ceramics, Polymers and Composites

Let’s look at the properties of ceramics, polymers and composites.

Ceramics

Ceramics are a class of materials that are made by shaping and moulding raw materials and then heating them to high temperatures. This process forms hard, strong and durable materials that can be used for many purposes. Two examples of ceramic materials are bricks and pottery.

Bricks are made by moulding clay and then baking them in an oven. They are typically used in construction for building walls, floors, and other structures.

Pottery is also made by moulding clay and firing it at high temperatures. Pottery is used to make a wide range of objects such as vases, bowls and plates.

Properties of ceramics

Ceramics have the following properties:

  • Very hard – makes them useful as building materials
  • Do not conduct electricity
  • High melting points – make them suitable for storing hot liquids
  • Brittle – they are likely to break or shatter under pressure

Polymers

Polymers are large molecules made up of repeating units known as monomers. These monomers are joined together through chemical reactions, to form long chains.

  • An example of a polymer is poly(ethene), which is formed by joining many ethene molecules together. The chemical structure of the ethene monomer is repeated throughout the polymer chain.

Another example is poly(chloroethene), which is formed by joining many chloroethene monomers.

In this case, the individual chloroethene molecules are linked together to form a polymer chain.

Natural polymers

Natural polymers are polymers that occur naturally in the environment. Two examples of natural polymers are wool and cotton.

Wool is produced by sheep.

Cotton is a natural polymer produced by cotton plants.

Both wool and cotton are used in textiles and clothing due to their softness, warmth and durability.

Synthetic polymers

Synthetic polymers are man-made materials created through chemical reactions. One common source of monomers for synthetic polymers is crude oil. It can be processed in oil refineries to produce different plastic polymers.

Here are some examples of plastic polymers:

Plastic polymerCommon uses
Low density poly(ethene) – LDPEPlastic bags
High density poly(ethene) – HDPEHarder plastics, such as bottles and toys
Poly(vinyl chloride) – PVCWater pipes and electronics

Properties and uses of polymers

Properties of polymers

  • Physical state: Typically solid at room temperature
  • Electrical conductivity: They are electrical insulators (do not conduct electricity). This makes them useful as insulation for electrical wires, as you can hold wires without getting an electric shock.
  • Strength: They possess a high tensile strength, so they do not break easily. This makes them useful for applications such as plastic bags, packaging and construction materials.
  • Reactivity: They are chemically unreactive, which makes them suitable for use as containers, to store food and liquids. However, there is a problem with polymers being unreactive. They do not break down very quickly, which can cause issues in landfill sites.

Uses of polymers

Polymer nameCommon uses
NylonClothes
PVCWater pipes and coating of electrical wires
poly(ethene)Plastic bags
LycraClothing usually sports clothing

Composites

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

For example, you can combine two materials with desirable properties to form a composite, which has the properties of both materials.

Reinforced concrete

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