Most plastics are made from oil. Plastics are man-made materials. They are a useful invention because they are waterproof, easy to shape and tough. They have taken the place of traditional materials like wood and metal in many products. It is bad to waste plastic, as it is made from non-renewable resources and takes a very long time to decay.
A bit of Chemistry
Plastics are made of Polymers which are obtained form monomers ( low-molecular-weight ) by polymerization reactions, in which large numbers of monomer molecules are linked together.
In the image on the left a monomer ethene ( C2H4) is used to produce a Polimer ( poliethene).
Ethene or Ethylene –because it contains a carbon-carbon double bond, ethylene is called an unsaturated hydrocarbon.
The process by which we get a polymer is called polymerization. This process has three stages: In the first stage, the monomer is split into two identical parts, each with an unpaired electron ( or free electron ). Now we have a free radical ( A molecule with an unpaired electron ). The free radical ( second line in the image ), forms a new bond with a ” neighbor atom ” This process repeats over and over again to form large chains containing thousands of carbon atoms.
There are two main types:
thermoplastic and thermosetting.
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