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PLASTICS, This depends on the outer coating applied by the final cylinder.…

- - - - 3. We cool the shaped material slowly in a refrigerated water bath until it's solid.
      - 1. We put thermoplastic, in granular form, into previously heated cylinder
      - 4. We collect the pieces of plastic through a feeder system.
      - 2. We apply pressure by means of a large, rotating screw, which forces the melted material out, through a nozzle.
  - - - 2. We then use a heater to heat the nould and soften the plastic.
      - 3. We extract the air below the sheet so that the plastic is pulled against the inside walls of the shaped mould, and the desired form is created.
      - 1. We put thermoplastic into a mould.
      - 4. We leave the mould to cool, then remove the object.
  - - - 2. We close the mould and blow pressurised air into it, so that the plastics adheres to its sides and takes its shape.
      - 3. When the object is cold, we remove it from the mould.
      - 1. We put a tubular-shaped piece of plastic into a hollow mould which has the shape of the object desired.
      - Used to form: hollowed objects, for example bottles and flasks.
    - - 3. The plastic adapts to the shape of the cavity between the two parts of the mould.
      - 4. We extract the object when the plastic has cooled and solidified.
      - 2. The outer part of the cavity mould, shaped the same, is closed to compress the material inside. We then heat it and it becomes soft and malleable.
      - Used to form: different types of containers, machine bodywork and electrical appliances
      - 1. We put thermostable plastic, which can be in granular form, into the base of a cavity mould.
    - - 1. We inject melted thermoplastic into a mould.
      - 2. When the material has cooled and solidified, we extract it from te mould.
      - Used to form: domestic utensils such as buckets and containers, vehicle and aircraft components
- - - - Synthetic plastics are made from compounds extracted from petroleum, natural gas and carbon. The majority of plastics belong to this group.
      - Natural plastics are obtained directly from raw vegetable materials - for example, cellulose or latex, or from animal proteins.
    - - During the manufacturing process, we can add materials such as fibreglass, textile fibres, paper, silica, and sawdust to reduce production costs, and to develop certain characteristics.
      - We can incorporate chemical additives to increase flexibility and to strengthen the polymers, and pigments to give colour to the plastic.
  - - - Electrical: electrical insulation
      - Thermal: thermal insulation
      - Acoustic: acoustic insulation
      - Other properties: low density, impermeability
      - Mechanical: malleability, ductility, mechanical resistance
  - - - Mechanical recycling. We make new products from plastic granules. The process has five stages:
        
        3. Agglutination. The material is compacted and then incorporated into other materials.
        
        4. Extrusion. We melt the material, and then it's extruded into long filaments.
        
        2. Floating. We wash the plastics and they dry them by centrifugal force.
        
        5. Pelletising. The filaments are then reduced to granules that we call pellets.
        
        1. Separation and crushing. We separate the plastics according to size and then they're crushed.
      - Energetic recycling. We can incinerate plastics and the energy that is produced is used in industry
      - Chemical recycling. We apply chemical processes to make new materials from the original components of plastic residues.
      - The majority of plastics aren't biodegradable yet. Thanks to new technologies we're increasingly able to produce more, like:
        
        plastics that dissolve in hot or cold water.
        
        plastics that decompose on contact with certain bacteria and biological agents.