-What monomers they are made from
-The conditions under which they are made
1 of 18
What three conditions could be changed to change the properties of a polymer?
-Change the reaction temperature
-Change the reaction pressure
-Change the catalyst
2 of 18
How are low density and high density poly(ethene) made differently?
They are both produced from ethene, using different catalysts and reaction conditions.
3 of 18
What are thermosoftening polymers?
-They melt when we heat them
-We can reshape them while they're soft
-Then they go back to a solid when we cool them back down
-Polymer chains are connected to each other by intermolecular forces
4 of 18
What happens when we heat/cool thermosoftening polymers (structure-wise)?
-When polymer is heated, the intermolecular forces break, so the polymer melts
-When the polymer is cooled, the intermolecular forces reform so it becomes a solid again
5 of 18
What are thermosetting polymers?
-They do not melt when we heat them
-Polymer chains are connected to each other by strong crosslinks
6 of 18
Why do thermosetting polymers not melt?
The strong crosslinks are not broken by heat
7 of 18
Name two types of ceramics
Glass ceramics
Clay ceramics
8 of 18
Most of the glass we use is ____ ____ ______, made by melting a mixture of ____, _______ _________ and _________.
Most of the glass we use is SODA-LIME GLASS, made by melting a mixture of SAND, SODIUM CARBONATE and LIMESTONE.
9 of 18
Does soda-lime glass have a low or high melting point?
A low melting point, which limits its uses
10 of 18
What is borosilicate glass?
-It is made by melting sand and boron trioxide.
-It has a higher melting point than soda-lime glass, which it makes it useful for objects that require heating
11 of 18
What uses are there of clay ceramics?
-Pottery
-Bricks
12 of 18
How are clay ceramics made>
Clay ceramics are made by shaping wet clay and then heating in a furnace to harden.
13 of 18
What are composites (include the types of materials)?
Most composites are made of two materials: fibres or fragments of the other material (reinforcement), which is surrounded by a matrix/binder material
14 of 18
Composites have different __________ to the materials in them.
Composites have different PROPERTIES to the materials in them.
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