Petroleum is made into a liquid hydrocarbon called styrene, which is then converted into polystyrene. This is through a chemical process known as suspension polymerization. Due to this type of plastic structure, polystyrene is incredibly difficult to degrade. Some examples include food packaging material, food trays, and other consumer polystyrene packaging such as polystyrene cups. Extruded polystyrene (XPS) is often used in ceiling insulation. Polystyrene’s toxic nature also makes some products hazardous, meaning they must be disposed of professionally.
Extruded polystyrene foam, also known as XPS, is made using a manufacturing process where polystyrene beads are heated and then extruded into shape. This process allows for a closed-cell structure, making XPS a good insulation material.
Expanded polystyrene, also known as EPS, is made by heating polystyrene beads, causing them to expand and take on a foamy structure. This forms a less dense and more lightweight structure than XPS. This is commonly used for a variety of products, including packaging for white goods.
There are three common methods of recycling, known as granulation, compacting, and densifying.
Granulation: Lighter density forms of polystyrene can go through a machine known as a granulator. This machine separates down to the tiny beads that make it up, which are then are mixed into unused polystyrene granules.
Compacting: For denser forms of polystyrene, they have to go into a compactor that presses them together. The resulting material is a very heavy and thick bale of pure polystyrene. These bales go through a machine that then shreds them into new General Purpose Polystyrene Pallets.
Densifying: There are other methods of recycling that are used less frequently, too. For instance, expanded polystyrene can be fed into a machine called a foam densifier.
Styrofoam is an extruded polystyrene (EXS). Although styrofoam is commonly more difficult to recycle, specialist businesses such as Plastic Expert can collect and recycle this waste in bulk loads.