Ceramics

Due to their high melting points and resistance to stains, ceramics are used in kitchen and dinnerware.

Glass Ceramics

  • Transparent and strong, glass ceramics insulate against heat and allow light to pass through, making glass the ideal material for making windows.
  • Glass ceramics are also more durable than other materials hence they are better suited for use in windows than plastic.
  • Most of the glass produced is soda-lime glass which is made by heating a mixture of limestone, sand and sodium carbonate (soda) until it melts.
  • On cooling it crystallises to form glass.
  • A variation is borosilicate glass which is made using sand and boron trioxide and has a higher melting point than soda-lime glass.

Clay Ceramics

  • These are hardened materials that resist compressive forces.
  • Clay is a soft material dug up from the earth which hardens at high temperatures.
  • Allows bricks to be used to build walls which withstand the weight and pressure of the material bearing downwards on itself.

Polymers

  • Poor conductors of heat and electricity, hence they are good thermal and electrical insulators.
  • These properties are extremely useful for insulating electrical wiring as they prevent electric shocks and overheating.

Electrical Wire Insulated, IGCSE & GCSE Chemistry revision notes

The polymer polyvinyl chloride (PVC) is commonly used to insulate electrical wiring

  • Depending on the manufacturing process used, the same polymer can have different properties.
  • Polythene for example can be made at high pressure and moderate temperature to produce low density polythene (LD) which is used for bags and bottles where flexibility is needed.
  • If it is produced at lower temperatures and pressure and with the use of a catalyst, a much higher density (HD) polythene is produced. This polymer has a more rigid, solid structure and is used to produce water tanks, mouldings, drain pipes etc.
  • Polymers can also be divided into thermosoftening and thermosetting polymers.
  • Thermosoftening polymers consist of individual chains entwined with each other with weak intermolecular forces holding the polymer chains together.
  • These polymers therefore have low melting points, can be melted and remoulded to form different shapes.
  • Thermosetting polymers on the other hand have strong cross-links between monomers on different polymer chains that hold the structure together.
  • These are strong and rigid structures that don’t soften under heating.

Composites

  • These are made from two components: reinforcement and matrix.
  • The reinforcement material is embedded in the matrix material which acts as a binder..
  • Common examples include fibreglass and steel reinforced concrete.
  • Wood is an example of a natural composite as it consists of cellulose fibres held together by an organic polymer mix.

Composites Table, IGCSE & GCSE Chemistry revision notes

  • The properties of composites depend on the reinforcement and matrix used so composites can be tailor engineered to meet specific needs.
  • Carbon fibres for example are extremely strong and low weight, hence they are used in aviation, aeronautics and for making professional racing bicycles.
  • Steel reinforced concrete has immense tensile and compressive strength allowing it to be used as columns and supporting structures in construction.

Steel Reinforced Concrete, IGCSE & GCSE Chemistry revision notes

Diagram showing a concrete beam which is reinforced with steel, providing much more tensile strength

AQA GCSE Chemistry Notes

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Morgan Curtin Chemistry

Author: Morgan

Morgan’s passion for the Periodic Table begun on his 10th birthday when he received his first Chemistry set. After studying the subject at university he went on to become a fully fledged Chemistry teacher, and now works in an international school in Madrid! In his spare time he helps create our fantastic resources to help you ace your exams.