Ceramics, Polymers And Composites

Ceramics

non-metallic solids with high melting points

Properties of ceramics

excellent inulators of both heat and insulators, very brittle

Examples of ceramics

clay, soda-lime glass & borosilicate glass

How is clay made?

-clay is soft and can be moulded into shape
-it is then fired at high temp and hardens

How is soda-lime glass made?

-a mixture of limestone, sand and sodium carbonate are heated until it melts
-when cooled glass is produced

How is borosilicate glass made?

-a mixture of sand and boron trioxide are heated then allowed to cool
-this glass has a higher melting point than soda-lime glass

Differences in properties of soda-lime glass and borosilicate glass

borosilicate glass:
-has a higher melting point
-is more durable
-more resistant to chemicals
-more resistant to temperature changes
-requires higher temperatures to manufactures and significantly more expensive

What are composites made up of?

two materials

Fibres or fragments

the reinforcement

A matrix or binder

surround the fibres or fragments

Examples of composites

concrete, wood, carbon fibre, fibreglass

Polymers

very large molecules (chains) formed when many small monomer molecules join together

What are the two different types of polythene?

high density (HDPE) & low density (LDPE)

Why do HDPE and LDPE have different properties despite being formed from the same monomer?

-the conditions to make the polymers are different
-with HDPE produced at higher temperature and pressure than LDPE

Thermosoftening polymers

-contains weak intermolecular forces
-melt when heated are the polymer chains are held together by weak intermolecular forces which do not require a lot of energy to overcome

Thermosetting polymers

-contains strong covalent bonds
-do not melt when heated as the polymer chains are held together by strong covalent bonds which require a lot of energy to overcome