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plastics - Coggle Diagram

- - - - natural plastics are obtained directly from raw vegetable materials -for example, cellulose or latex, or from animal proteins
    - - sinthetic plastics are made from compounds extracted from petroleum, natural gases and carbon. the majority of plastics belong to this group.
    - - 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 strength the polymers, and we can add pigments to give colour to the plastics.
  - - - mechanical: malleability, ductility, mechanical resistance
      - acoustic: acoustic insulation
      - electrical: electrical insulation
      - thermal: thermal insulation
      - other properties: low density, impermeabilty
  - - - energetic recycling
        
        We can incinerate plastics and the energy that is produced is used in industry, for heating or producing electricity.
      - mechanical recycling
        
        We make new products from plastic granules The process has five stages.
        
        Floating. we wash the plastics and then dry them by centrifugal force
        
        Extrusion. we melt the material, and then it's extruded into long filaments
        
        separation and crushing. we separate the plastics acording to type and then they´re crushed
        
        Agglutination. The material is compacted and then incorporated into other materials
        
        Pelletising. The filaments are then reduced to granules that we call pellets.
      - chemical recycling
        
        We apply chemical processes to make new materials from the original components of plastic residues.
- - - - We use plastic sheets with a large surface for this technique
        
        We extract the air below the sheet so that the plastic ts pulled against the instde walls of the shaped mould, and the desired form is created
        
        We put thermoplastic into a mould.
        
        We leave the mould to cool, then remove the obiect
        
        We then use a heater to heat the mould and soften the plastic.
    - - This technique has four stages
        
        We apply pressure by means of a large, rotating screw, which forces the melted material out, through a nozzle.
        
        Finally, we collect the pieces of plastic through a feeder system.
        
        We put thermoplastic, in granular form, Into a previously heated cylinder
        
        We cool the shaped material slowly in a refrigerated water bath until it´s solid.
    - - blow moulding
        
        We close the mould and blow pressurised air into it, so that the plastic adheres to the sides of the mould and takes its shape.
        
        When the object is cold, we remove it from the mould.
        
        We put a tubular-shaped piece of plastic into a hollow mould which has the same shape as the object that we want to make
        
        Used to form: hollow oblects, for example bottles and flasks.
      - compression
        
        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 maleable.
        
        The plastic adapts to the shape of the cavity between the two parts of the mould
        
        We put thermostable plastic which can be in granular form, into the base of a cavity mould.
        
        We extract the object when the plastic has cooled and solidified
        
        Used to form: different types of containers, machine bodywork and electrical appliances
      - injection moulding
        
        We inject melted thermoplastic into a mould
        
        When the material has cooled and solidified, we extract it from the mould
        
        Used to form: domestic utensils such as buckets and contatners, vehicle and aircraft components
    - - Thermoplastic produced by the extrusion method is passed through a series of hot cylinders to produce sheets of varying thickness. With this technique, we can produce different finishes, for example, glossy, matt or textured. This depends on the outer coating applied by the final cylinder.