What Is EPS or Expanded Polystyrene?

Lightweight and Strong Foam

EPS is used to make insulation
EPS is used to make insulation. eyenigelen/E+/Getty Images

EPS (Expanded Polystyrene) is an extremely lightweight product that is made of expanded polystyrene beads. Originally discovered by Eduard Simon in 1839 in Germany by accident, EPS foam is more than 95% air and only about 5% plastic.

Small solid plastic particles of polystyrene are made from the monomer styrene. Polystyrene is normally a solid thermoplastic at room temperature that can be melted at a higher temperature and re-solidified for desired applications. The expanded version of polystyrene is about forty times the volume of the original polystyrene granule.

Uses of Polystyrene

Polystyrene foams are used for a variety of applications because of its excellent set of properties including good thermal insulation, good damping properties and being extremely light weight. From being used as building materials to white foam packaging, expanded polystyrene has a wide range of end-use applications. In fact, many surfboards now use EPS as the foam core.

Building and Construction

EPS is inert in nature and therefore does not result in any chemical reactions. Since it will not appeal to any pests, it can be used easily in the construction industry. It is also closed cell, so when used as a core material it will absorb little water and in return, not promote mold or rotting.

EPS is durable, strong as well as lightweight and can be used as insulated panel systems for facades, walls, roofs and floors in buildings, as flotation material in the construction of marinas and pontoons and as a lightweight fill in road and railway construction.


EPS has shock absorbing properties making it ideal for storing and transporting fragile items such as wines, chemicals, electronic equipment, and pharmaceutical products. Its thermal insulation and moisture resistant properties are perfect for packaging cooked food as well as perishable items such as seafood, fruit, and vegetables.

Other Uses

EPS can be used in the manufacture of sliders, model planes, and even surfboards because of its positive strength to weight ratio. The strength of EPS along with its shock absorbing properties makes it effective for use in children’s seats and cycling helmets. It is also compression resistant, meaning that EPS is ideal for stacking packaging goods. EPS also has applications in horticulture in seedling trays to promote aeration of the soil.

Why Is EPS Advantageous?

  • High thermal insulation
  • Resistant to Moisture
  • Extremely durable
  • Easily recyclable
  • Versatile in strength
  • Easily laminated with epoxy resin
  • Manufactured into different shapes, sizes, and compression materials
  • Lightweight and portable
  • High shock absorbency characteristics
  • Compression resistant
  • Branded by printing or adhesive labeling.

Drawbacks of EPS

  • Not resistant to organic solvents
  • Cannot be used in combination with MPVC hydro-insulation foils
  • Previously, EPS was made from Chlorofluorocarbons which damaged the ozone layer
  • Flammable if oil painted
  • Health concerns with styrene chemicals seeping into hot beverages or food placed in EPS cups

Recycling EPS

EPS is completely recyclable as it will become polystyrene plastic when recycled. With the highest recycling rates for any plastic and accounting for a non-substantial portion of municipal waste, expanded polystyrene is an environmentally friendly polymer. The EPS industry encourages recycling of packaging material and many large companies are successfully collecting and recycling the EPS.

EPS can be recycled in many different ways such as thermal densification and compression. It can be reused in non-foam applications, lightweight concrete, building products and remolded back into EPS foam.

Future of EPS

With the considerable number of applications, EPS is being used as a result of its excellent range of properties, the future of the EPS industry is bright. EPS is a cost-effective and friendly polymer best for insulation and packaging purposes.

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Johnson, Todd. "What Is EPS or Expanded Polystyrene?" ThoughtCo, Sep. 8, 2021, thoughtco.com/what-is-eps-expanded-polystyrene-820450. Johnson, Todd. (2021, September 8). What Is EPS or Expanded Polystyrene? Retrieved from https://www.thoughtco.com/what-is-eps-expanded-polystyrene-820450 Johnson, Todd. "What Is EPS or Expanded Polystyrene?" ThoughtCo. https://www.thoughtco.com/what-is-eps-expanded-polystyrene-820450 (accessed June 8, 2023).