[materials] using materials

[ https://www.bbc.co.uk/bitesize/guides/ztrwng8/revision/4 ]

Properties of Glass:

• transparent

• hard

• brittle

Types of Glass:

• soda-lime glass

• borosilicate

Soda-lime Glass

Glass made by heating a mixture of sand, sodium carbonate and limestone. This is the most common type of glass.

Borosilicate

Glass made by heating sand and boron trioxide; has a higher melting point than soda-lime glass.

Properties of Ceramics:

• non-metal solids

• electrical insulators

• high melting point

• brittle

Clay Ceramics

Made by shaping wet clay and then heating it in a furnace. They can be coated with a glaze, which hardens on heating to form a hard, smooth, opaque and waterproof layer.

Polymer

A large molecule formed from many identical smaller molecules known as monomers.

Thermosetting Polymers

Polymers which contain special monomers that form cross-links between the polymer chains. These polymers do not soften when heated, they are strong, hard and rigid.

Thermosoftening Polymers

Polymers which contain individual polymer chains, weak forces between chains, you can melt these plastics and re-mould them. They do not contain covalent bonds.

Low Density Polyethene (LDPE)

Polyethene made from ethane at moderate temperatures, under high pressure with a catalyst.

Properties of LDPE:

• flexible

• unreactive

• can be made into films

High Density Polyethene (HDPE)

Polyethene made from ethane at lower temperatures and a different catalyst than LDPE.

• flexible

• strong

• resists shattering

• resists chemical attack

Composite Materials

Materials that have another material embedded within it.

Composite Materials have 2 Components:

• the reinforcement

• the matrix, which binds the reinforcement together

Examples of Composites:

• fibre glass

• reinforced

• concrete

• wood

Overall Properties of Composites:

• strong

• stiff

• lightweight

Reinforcement

Fibres or other material that make up the bulk of a composite material.

Matrix

The substance that binds the reinforcement together in a composite material.

Reinforced Concrete

• reinforcement → steel (high tensile strength)

• matrix → concrete (high compressive strength)

Fibreglass

• reinforcement → glass fibres; low density, strong in tension & flexible

• matrix → polymer resin

Carbon Fibre Reinforced Polymer (CFRP)

• reinforcement → carbon fibres; low density, strong in tension & flexible

• matrix → polymer resin

Chipboard

• reinforcement → wood chips

• matrix → resin glue

• contains randomly arranged wood chips bonded together by glue; strong in all directions