Expanded polystyrene (EPS) foam, commonly known by the brand name Styrofoam, serves a wide range of applications in daily life. This lightweight material is widely used for packaging delicate items, forming food containers, and providing insulation in construction due to its thermal properties. Its composition, which is typically 98% air, contributes to its low density and makes it an effective protective and insulating agent. However, this airy structure also presents challenges for waste management because of the significant volume it occupies and its slow decomposition rate in landfills. Addressing the disposal of this material involves understanding how it can be recycled into new products.
Products from Recycled Styrofoam
Recycled EPS can be transformed into a variety of new materials and goods. These include:
New polystyrene products like clothes hangers, plastic cutlery, and new foam packaging.
Construction materials such as insulation boards, lightweight concrete additives, and components for structural insulated panels.
Architectural elements like decorative moldings, picture frames, and baseboards.
Outdoor and everyday items including park benches, garden furniture, flower pots, and decking materials.
Recycled polystyrene is generally not used for products that come into direct contact with food due to potential contamination concerns.
How Styrofoam is Transformed
The transformation of expanded polystyrene into a recyclable material begins with careful collection and sorting. Recyclers prioritize clean, uncontaminated foam, free from food residue, tape, or labels, as contaminants hinder the recycling process and reduce the usability of the recycled material. Once collected, the bulky foam undergoes a volume reduction process known as densification.
Densification methods include mechanical compaction, where the foam is shredded and then compressed into dense blocks or ingots, reducing its volume by up to 50 times. Another technique is thermal densification, where the foam is heated and melted into a thick paste, which is then extruded and solidified into a dense form. This melting process can achieve even greater volume reduction, sometimes up to 90 times the original size. The densified material is then typically pelletized, producing small, uniform plastic pellets (recycled General Purpose Polystyrene or rGPPS) that serve as raw material for manufacturing new products. These pellets can be blended with virgin polystyrene or other materials depending on the specifications of the desired new product.
Making Styrofoam Recycling More Common
Increasing the prevalence of Styrofoam recycling involves a multi-faceted approach, focusing on specialized collection, technological advancements, and collaborative efforts. Curbside recycling programs often do not accept expanded polystyrene due to its bulkiness and potential for contamination, necessitating dedicated collection points. Many communities offer specialized drop-off locations or even mail-back programs for clean foam.
Technological progress plays a role in improving recycling efficiency. Innovations in densification equipment, such as advanced foam densifiers, make the process more economically sound by reducing transportation costs. Researchers are also exploring chemical recycling methods, such as pyrolysis, which break down polystyrene into its basic monomers for reconstitution into new, high-purity material. Another emerging technique involves using ultraviolet light and a chemical catalyst to convert polystyrene into chemical compounds like diphenylmethane (DPM).
Industry initiatives and partnerships are also expanding recycling access and fostering circular systems. Organizations such as the Polystyrene Recycling Alliance (PSRA) bring together manufacturers, recyclers, and brands to invest in infrastructure and education to make polystyrene widely recyclable. Companies are collaborating to create closed-loop systems, ensuring that recycled polystyrene is reintegrated into manufacturing processes. Consumer awareness and proper preparation of the material, such as cleaning and removing labels, also contribute to the success of these recycling efforts.