KEY CONCEPTS

To start I'm going to give the key concepts of this unit, the key concepts are a small sumary of the important part of the unit:

• Plastics consist of long chains of atoms which are mostly composed of carbon.
• Plastics can be classified into natural and synthetic plastics.
• The process of manufacturing plastic is called polymerisation.
• Plastic materials are resistant insulating(against electricity,heat and sound) ductile, malleable, impermeable adn light.
• There are three tyoes of plastic recycling processes:Chemical and mechanical recycling and energy recovery.
• Thermoplastics are usually made from petroleum products.The most common thermoplastics are:Polyethylene terephthlate(PET), high-density polyethylene, polyvinyl chloride(PVC),low-density polythylene, polypropylene, moulded polysthyrene and expanded polystyrene or Styrofoam.
• Thermosetting plastics are made from petroleum products.They include:Polyurethane, bakelite, melamine and polyester resins.
• Typical elastomers include rubber and neoprene.
• Various industrial techniques can be used to manufacture plastic products, such as: extrusion, calendering, vacuum forming and moulding.
• The main techniques for using moulds are as follows:Blow moulding, injection moulding and compression moulding.
• Modification techniques use tools and machines to make changes to prefabricated materials, such as sheets,bars and mouldings.
  
• Example of these techniques include:measuring->drawing->marks and lines->cutting->drilling->filing and sanding->joining.
• You must always pay special attetion to health and safety rules.
• Both natural and synthetic fibres can be woven to make a variety of textiles.
• Natural fibres may come from animal sources(woll,silk), plant sources(cotton,linen,esparto,bamboo) and mineral sources(gold,silver and copper fibres).
• Synthetic fibres, such as nylon,polyester,rayon and Lycra, are plastic materials.