Polystyrene is a petroleum byproduct that is used to make products ranging from food storage containers to household goods. Polystyrene blocks and packing peanuts also serve as some of the most popular materials for shipping and packaging. Though manufacturers continue to use these products in large quantities, many people are concerned about how polystyrene disposal may impact the environment. Concerns over pollution and disposal have led some companies to develop polystyrene recycling techniques, including crushing, dissolving, or reusing this material to make new products.
One of the most basic methods of polystyrene recycling involves melting this material down in a specialty oven. These recycling ovens are designed to meet the demands of polystyrene recycling, and can shrink this material to just a fraction of its size by removing excess air. The resulting by-product largely consists of petroleum, and can be sold to refineries for use in diesel fuel. Others use chemicals or organic compounds, including a citrus oil known as limonene, to dissolve the polystyrene without the use of these ovens.
Polystyrene foam products, including insulation and packing materials, can be recycled to form new building materials. Manufacturers shred on grind the polystyrene into small pieces, then add it to concrete mixtures to enhance the insulating properties of the concrete. Polystyrene recycling may also include turning this foam into loose fill insulation for homes and buildings. Some manufacturers even press the loose foam pieces into sheets of foam building insulation. Recycled polystyrene foam also serves as an important component in structural insulated panels (SIPs).
Another form of polystyrene recycling involves melting these products and pouring them into molds to form new products. For example, some manufacturers produce benches, picture frames, and household goods using petroleum-derived thermoplastic materials. By melting existing polystyrene products instead, manufacturers can avoid seeking out raw materials. This type of recycling process is also used to produce molds for casting metal or other forms of plastic.
Consumers have many several options when it comes to choosing a polystyrene recycling method. Some retailers collect used polystyrene products for in-house recycling, or for use in making new products. Many communities also provide curbside pickup of these material, or accept these products for dropoff at local recycling centers. Mailing and shipping companies may take packing materials and reuse them to package future products. Some polystyrene industry associations also accept these products by mail, and then arrange for recycling or reuse.