Key concepts

• 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 plastics is called polymerisation.
• Plastic materials are resistant, insulating (aganist electricity, heat and sound), ductile, malleable, impermeable and light.
• Threre are three types of plastic recycling processes: chemical and mechanical recycling and energy recovery.
• Thermoplastics are usually made from petroleum products. The most common thermoplastics are: 

      - Polyethylene terephthalate (PET).
      - High-density polythylene.
      - Polyvinyl chloride (PVC).
      - Low-density polyethylene.
      - Polypropylene.
      - Moulded polystyrene.
      - Expanded polystyrene or Styrofoam.

• Thermosetting plastics are made from petroleum products. They include:

      - Polyurethane

      - Bakelite

      - Melamine

      - Polyester resins

• Typical elastomers incluide 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 or moulding.
• Both natural and synthetic fibres can be woven to make a variety of textiles. 
• Natural fibres may come from animal sources (wool, 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.