Polymer Chemical Information
| HDPE
|
High Density Polyethylene |
| LDPE |
Low Density Polyethylene |
| PP |
Polypropylene |
| PA |
Polyamide |
| EVOH
|
Ethylene Vinyl Alcohol (used in multi-layer containers
as a barrier against oxygen ingress) |
| PET |
Polyethylene Teraphthalate |
Where they come from/How they are produced:
How is Polyethylene (PE) Made?
Naphtha is another word for petroleum and is an intermediary
product in the oil refining process. By heating the naphtha
very intensely ("cracking"), the gas ethylene is
produced. Under the controlled conditions in the cracking
tower, the ethylene gas molecules link together(polymerisation)
to form long chains to produce polyethylene, a substance that
looks like liquid porridge. A constant stream of this material
is extruded through a 'mincing plate' before it sets. These
'strings' are finely cut to form granules.
The conditions of the process determine of the polyethylene
produced is High Density or Low Density. Polypropylene is
produced in the same way using Propylene monomer. PET, PA
and EVOH are produced by more complex production processes.
The table below indicates the inherent properties of each
of the basic polymer types in comparison to each other.
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