ceramics, polymers & composites

Question 1

what are ceramics?

Answer 1

non-metal solids with high melting points that aren’t made from carbon-based compounds

Question 2

what are some ceramics made of?

Answer 2

clay

Question 3

clay

Answer 3

-soft material when dug up out of the ground
-can be moulded into different shapes when wet
-hardens to form a clay ceramic when heated in a furnace
-ideal for making pottery and bricks

Question 4

glass

Answer 4

-example of a ceramic
-generally transparent
-moulded when hot
-brittle when thin

Question 5

what is type of glass is most common?

Answer 5

soda-lime

Question 6

how is soda-lime glass made?

Answer 6

heating a mixture of limestone, sand and sodium carbonate (soda) until it melts, then cool to form glass

Question 7

how is borosilicate glass made?

Answer 7

by heating a mixture of sand and boron trioxide until it melts

Question 8

which glass has a higher melting point?

Answer 8

borosilicate

Question 9

what are composites?

Answer 9

-material made of two separate materials, embedded in each other
-fibres or fragments of a material (known as the reinforcement) are surrounded by a matrix acting as a binder

Question 10

what do the properties of composites depend on?

Answer 10

the properties of the material it is made from

Question 11

fibreglass

Answer 11

-consists of fibres of glass embedded in a matrix made of polymer
-low density
-very strong
-used for skis, surfboards, boats

Question 12

carbon fibre

Answer 12

-polymer matrix
-reinforcement is made from long chains or carbon atoms bonded together or from carbon nanotubes
-composites are strong
-lightweight
-used in aerospace and sports car manufacturing

Question 13

concrete

Answer 13

-made from aggregate embedded in cement
-very strong
-building material

Question 14

wood

Answer 14

-natural composite
-cellulose fibres held together by an organic polymer matrix

Question 15

what does the properties of polymers depend on?

Answer 15

what monomers they are made from and the conditions under which they are made

Question 16

list 5 properties of most polymers

Answer 16

-non-biodegradable
-high tensile strength
-withstand high temperatures
-morphed into shapes
-strong

Question 17

LDPE

Answer 17

-low density poly(ethene)
-made at a moderate temperature (200°C) and a high pressure (2000atm) with no catalyst
-polymer chains have side branches that stop polymer molecules from lining up regularly, preventing tight packing
-weak intermolecular forces
-flexible
-low density
-used for bags and bottles

Question 18

HDPE

Answer 18

-high density poly(ethene)
-made at a low temperature (60°C) and a low pressure with a catalyst
-no side branches so polymer molecules line up regularly in tightly packed chains
-strong intermolecular forces
-rigid
-high density
-used for water tanks and drainpipes

Question 19

thermosetting

Answer 19

-contain monomers that can form cross-links between the polymer chains, holding the chains together in a solid structure
-don’t melt when heated so can’t be reshaped once moulded
-strong
-hard
-rigid

Question 20

thermosoftening

Answer 20

-contain individual polymer chains entwined together with weak forces between the chains
-melt when heated so can be remoulded

Question 21

ceramic overview

Answer 21

-include glass and clay
-porcelain and bricks
-thermal and electrical insulators
-brittle
-stiff

Question 22

composites overview

Answer 22

properties depend on the matrix/binder and reinforcement used to make them
many different uses

Question 23

polymers overview

Answer 23

-electrical and thermal insulators
-can be flexible
-can be easily moulded
-many applications including clothing and insulators in electrical items

Question 24

metals overview

Answer 24

-generally malleable
-conductors of heat and electricity
-ductile
-shiny
-stiff
-many uses
-electrical wires
-car bodywork
-cutlery