Polystyrene Fast Facts

POLYSTYRENE, or PS, is a thermoplastic substance created from styrene, an aromatic monomer.

This aromatic polymer is colorless with little flexibility in its pure, sold plastic form. Polystyrene is commonly used in fine detailed molds. It is available transparent and in a variety of colors. Certain forms of PS are highly demanded for their low cost and insulation properties.

Solid polystyrene is used to make disposable cutlery, plastic models, and CD/DVD cases.

PS is manufactured in three forms: extruded polystyrene and expanded or extruded polystyrene foam.

Because of expanded polystyrene foam’s (EPS) wide range in density, it is used in many different products ranging from high-density surfboards to foam cups commonly used in “fast food” industries in the US, Japan, Australia, and New Zealand.

While PS can be cut with a typical cutter, it can also be cut with a hot-wire foam cutter for exceptionally smooth cuts and an easier process. The wire never actually makes contact with the foam, but emits a heat that melts the foam before contact. Hot wire cut foam is generally used in signage, architecture models, movie sets, and amusement parks.

XPS, or extruded polystyrene foam, is most commonly known by the name Styrofoam. This form of PS had moderate flexibility, a low density, and a low thermal conductivity. XPS has versatile usage from packing “peanuts” and other packing materials to building insulation in construction to material used in crafts and model building.

Polystyrene is labeled under the resin identification code, or recycling code, as 6. It is non-biodegradable and should be disposed of properly. PS must be incinerated at appropriate temperature and oxygen levels and produces only water, carbon dioxide, carbon soot, and a complex mixture of volatile compounds. Improper incineration can lead to styrene monomers, polycyclic aromatic compounds, carbon black, and carbon monoxide.

FUN FACT: Under correct incineration, PS foam cups produce only 0.2 ounces of ash per ton compared to the average 200 pounds per ton from paper cups.