Ceramaics, polymers and composites/ NPK fertilisers Flashcards
What are ceramics?
non-metal solids with high melting points that aren’t made from carbon-based compounds
How are ceramics made?
by shaping wet clay and then heating it in a furnance
Why is clay hard hut but brittle?
include the type of bonds it contains
because it is a mixture of compounds containing both ionic and covalent bonds and when it goes from wet to dry in the furnace a regular crystilla structure is produced where the atoms and compounds are held together by strong bonds throughout the ceramic
What are the properties of clay?
- hard
- Brittle
- electric insulators
- resistant to corrosion
What are the two types of glass?
soda-lime and Borosilicate
How is soda- lime glass made?
by heating a mixture of sand, sodium carbonate and limestone unitl it melts then let it cool
How is Borosilicate made?
made from sand and boron trioxide
it melts at higher temeratures than soda lime glass
what is Borosilicate used to make?
chemical glassware, cooking equipment and car headlights
What are composite materials?
materials that consist of two materials with different properties
the materials are combined together to produce a material that ahs its own improved properties
Describe the structure of a composite material?
fibres or fragments of a material (aka reinforcement) are surrounded by a matrix acting as a binder
What to the properties of polymers depend on?
What monomers they are made from and the condition under which they ere made in
How is low-density poly(ethene) produced from ethene?
the moderate temperature under high pressure with a catalyst
flexible
used for bags and bottles
How is high-density poly(ethene) produced from ethene?
produced at a lower temperature and pressure with a different catalyst
more rigid and used for water tanks and drain pipe
Describe what are thermosoftening polymers
- melt when they are heated
- polymer chains have weak intermolecular forces between them
Describe what are thermosetting polymers
do not melt when they are heate
polymer chains are connected to each other by strong covalent bonds called cross-links, holding the chains together in a solid structure
- dont soften when they’re heated.
strong, hard and rigid
