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PLASTICS (PROPERTIES OF PLASTICS (These are other chatacteristics that are…

- - - - The transformation of these raw materials and compounds into plastic is called polymerisation
        
        During the manufacturing progress, 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 we can add pigments to give colour to the plastics
- - - - Chemical recycling
        
        We apply chemical processes to make new materials from the original components of plastic residues
      - Mechanical recycling
        
        We make new products from plastic granules. The process has five stages:
        
        1. Separation and crushing: We separate the plastics according to type and then they're crushed
        
        2. Floating: we wash the plastics and then dry them by centrifugal force
        
        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
        
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      - Energetic recycling
        
        We can incinerate plastics and the energy that is produced is used in industry, for heating or producing electricity
- - - - This technique has 4 stages:
        
        1. We put thermoplastic, in granular form, into a previously heated cylinder
        
        2. We apply pressure by means of a large rotating screw, which forces the melted material out, through a nozzle
        
        3. We cool the shaped material slowly in a refrigerated water bath until it's solid
        
        4. Finally, we collect the pieces of plastic through a feeder system
    - - 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
    - - We use plastic sheets with a large surface for this technique
        
        This technique has 4 stages:
        
        1. We put thermoplastic into a mould
        
        2. We then use a heater to heat the mould 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
        
        4. We leave the mould to cool, then remove the object
    - - There are three principal techniques
        
        Injection moulding
        
        Used to form domestic utensils such as buckets and containers, vehicle and aircraft components
        
        Blow moulding
        
        Used to form hollow objects, for example bottles and flasks
        
        Compression
        
        Used to form different types of containers, machine bodywork and electrical appliances
- - - - Cutter
      - Scissors
      - Steel bit
      - Fretsaw
      - Jig saw
      - Power press
      - Hot metal thread trimmer
    - - Drill bit
    - - File
      - Rasp
- - - - Mechanical fasteners
    - - Adhesives
        
        resins with two components
        
        acrylic cement
        
        contact adhesives
      - Soldering
        
        Joining thermoplastics using heat and pressure