PLASTICS
Plastics are materials formed by polymers. The polymers in plastics are made from long chains of carbon atoms.
Origin and transformation of plastics
Natural plastics are obtained directly from raw vegetable matenals
Synthetic plastics are made from compounds extracted frompetroleum, natural gas and carbon The maionty of plastics belong to thrs group.
Depending on their origin, we can describe plastics as natural or
syntheuc:
. Properties of plastics
acoustic: acoustic insulation
electrical: electncal rnsulation
mechanical: malleabrlity, ductility, mechanical resrstance
t hermaL thermal rnsulat ion
other properties: low density, tmpermeabihty
Ecological properties
Chemical recycling. We apply chemical processes to make netv
matenals from the ongtnal components of plasuc residues.
Mechanical recycling. We make new products from plastic
granules.
Energetic recycling. We can incinerate plastics and the energy that is produced is used tn industry, for heating or producing electnctty.
Classification of plastics
Thermoplastics
They' re made up of weakly formed molecular chains
Thermostable plastics
These plastics are made from compounds dertved from petroleum
. Elastomers
Made by vulcanisationi mixing sulphur and rubber,
Formation techniques
. Extrusion
Lamination
Vacuum forming
. Moulding
There are three pnnctpal techniques:
• inlection
• blow moulding
• compression.
We use plastic sheets with a large surface for this technique
Thermoplastic produced by the extrusion method ls passed through a senes of hot cylinders to produce sheets of varying thtckness
Used to form; wrapptng, hntng for electnc cables, tubes and pipes