|
History
The first plastics were made in about 1860,
but it was the 1950's when plastic began to be used a lot. After
the Second World War. Now, they are replacing traditional materials
like wood and metal.
Making Plastics
Plastic is a man-made material. It is made
from chemicals found in crude oil. These chemicals are taken out
of the oil and mixed together to make many different sorts of plastics.
Two families of plastics are
Thermoplastic
Thermoplastics soften when heated and can
then be formed into different shapes. They keep this shape when
they cool. They can be reheated several times. This type of plastic
is used to make things like yoghurt pots, mobile phones and pop
bottles.
PLASTICS SOFTEN
THEY DO NOT MELT.
Thermosetting Plastics
These plastics are stiffer and stronger than
Thermoplastics. It will not soften. Because this plastic does not
go soft when heated it can be used to make kettles, electrical plugs
and saucepan handles.
|