Polystyrene (PS) is a multi-faceted plastic used in many common items. The resin identification code for this plastic is "6." PS (solid or foamed) starts as a liquid monomer and is made into a stable, solid polymer pellet. To turn the pellets into PS foam, they are impregnated with a blowing agent, such as pentane or carbon dioxide. This transforms them into “pre-puff” beads. The beads are then heated and puffed up like popcorn. These beads are made into cups, plates, and containers through thermoforming or steam-chest molding.
Recycling facilities for foam PS cups, clamshells, and trays are limited; however, access is increasing in the U.S. and Canada. Please check with your local recycler to see if PS is accepted in your recycling program, or visit the polystyrene foam recycling map to search for a recycler near you.
Learn more about foam recycling in the U.S.