PLASTICS

Plastics are materials formed by polymers. The polymers in plastics are made from long chains of carbon atoms.

Origin and transformation of plastics

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Natural plastics are obtained directly from raw vegetable matenals

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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:

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. 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

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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

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Thermoplastic produced by the extrusion method ls passed through a senes of hot cylinders to produce sheets of varying thtckness

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Used to form; wrapptng, hntng for electnc cables, tubes and pipes

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