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This article is about the Styrofoam brand. For food containers, see Foam food container. For the musician, see Styrofoam (musician).

Styrofoam is a trademarked brand of closed-cell extruded polystyrene foam currently made for thermal insulation and craft applications. It is owned and manufactured by The Dow Chemical Company.[1]

In the United States and Canada, the word styrofoam incorrectly refers to expanded (not extruded) polystyrene foam, such as disposable coffee cups, coolers, or cushioning material in packaging, which is typically white and is made of expanded polystyrene beads.[1] The term is used generically although it is a different material from the extruded polystyrene used for Styrofoam insulation. The Styrofoam brand polystyrene foam, which is used for craft applications, can be identified by its roughness and the fact that it "crunches" when cut. As well, it is moderately soluble in many organic solvents, cyanoacrylate, and the propellants and solvents of spray paint. Another tradename for polystyrene foam is thermacol, originated by BASF for expanded polystyrene.


In 1941, researchers in Dow's Chemical Physics Lab found a way to make foamed polystyrene. Led by Ray McIntire, they "rediscovered" a method first discovered by Swedish inventor Carl Georg Munters.[2] Dow acquired exclusive rights to use Munters' patents and found ways to make large quantities of extruded polystyrene as a closed cell foam that resists moisture.


Styrofoam is composed of ninety-eight percent air, making it lightweight and buoyant.[3] Because of its insulating properties and buoyancy, it was adopted in 1942 by the United States Coast Guard for use in a six-person life raft.

Styrofoam has since found a variety of uses. Dow produces Styrofoam building materials, including varieties of insulated sheathing and pipe insulation. The claimed R-value of Styrofoam insulation is five per inch.[4]

Dow also produces Styrofoam as a structural material for use by florists and in craft products.[5] Dow insulation Styrofoam has a distinctive blue color; Styrofoam for craft applications is available in white and green.

Styrofoam can be used under roads and other structures to prevent soil disturbances due to freezing and thawing.[6][7]

Environmental effects[edit]

The EPA and International Agency for Research on Cancer have determined styrene as a possible human carcinogen.[8][9] The National Bureau of Standards Center for Fire Research found 57 chemical by-products released during the combustion of expanded polystyrene foam.[10]

See also[edit]


  1. ^ a b "STYROFOAM™ - It's Not a Cup" Dow Chemical Company
  2. ^ Boundy, Ray H.; Amos, J. Lawrence (1991). A History of the Dow Chemical Physics Lab. New York: Marcel Dekker, Inc. pp. 117–128. ISBN 0-8247-8097-3. 
  3. ^ "How is Polystyrene (styrofoam) made?". StyroMelt. Retrieved 2012-06-23. 
  4. ^ Dow Announces New Technology for STYROFOAM Insulation
  5. ^ "STYROFOAM Brand Foam Crafts". Retrieved 2010-12-31. 
  6. ^ "Geotechnical applications of Styrofoam". Dow Chemical. Retrieved 2009-10-28. 
  7. ^ "Engineering considerations when building on permafrost". Retrieved 2007-08-30. 
  8. ^
  9. ^
  10. ^

External links[edit]