Styrofoam is a brand of closed-cell extruded polystyrene foam (XPS), manufactured to provide continuous

building insulation Building insulation is material used in a building (specifically the building envelope) to reduce the flow of thermal energy. While the majority of insulation in buildings is for thermal insulation, thermal purposes, the term also applies to ...

board used in walls, roofs, and foundations as

thermal insulation Thermal insulation is the reduction of heat transfer (i.e., the transfer of thermal energy between objects of differing temperature) between objects in thermal contact or in range of radiative influence. Thermal insulation can be achieved with s ...

and as a water barrier. This material is light blue in color and is owned and manufactured by

DuPont Dupont, DuPont, Du Pont, duPont, or du Pont may refer to: People * Dupont (surname) Dupont, also spelled as DuPont, duPont, Du Pont, or du Pont is a French surname meaning "of the bridge", historically indicating that the holder of the surname re ...

. DuPont also has produced a line of green and white foam shapes for use in crafts and floral arrangements. The term ''styrofoam'' has become a

genericized trademark A generic trademark, also known as a genericized trademark or proprietary eponym, is a trademark or brand name that, because of its popularity or significance, has become the generic term for, or synonymous with, a general class of products or ...

; it is often used in the United States as a colloquial term to refer to expanded (not extruded)

polystyrene foam Polystyrene (PS) is a synthetic polymer made from monomers of the aromatic hydrocarbon styrene. Polystyrene can be solid or foamed. General-purpose polystyrene is clear, hard, and brittle. It is an inexpensive resin per unit weight. It is a ...

(

EPS An extended play (EP) is a Sound recording and reproduction, musical recording that contains more tracks than a Single (music), single but fewer than an album. Contemporary EPs generally contain up to eight tracks and have a playing time of 1 ...

). Outside the United States, EPS is most commonly referred to as simply "polystyrene" with the term "styrofoam" being used in its capacity to describe all forms of extruded polystyrene, not just the Dupont brand itself. Polystyrene (EPS) is often used in food containers, coffee cups, and as cushioning material in

packaging Packaging is the science, art and technology of enclosing or protecting products for distribution, storage, sale, and use. Packaging also refers to the process of designing, evaluating, and producing packages. Packaging can be described as a coo ...

. Styrofoam is, however, a far less dense material than EPS and is more commonly suited to tasks such as thermal insulation. Additionally, it is moderately soluble in many organic solvents,

cyanoacrylate Cyanoacrylates are a family of strong fast-acting adhesives with industrial, medical, and household uses. They are derived from ethyl cyanoacrylate and related esters. The cyanoacrylate group in the monomer rapidly polymerizes in the presence ...

, and the propellants and solvents of

spray paint Spray paint (formally aerosol paint) is paint that comes in a sealed, pressurized can and is released in an aerosol spray when a valve button is depressed. The propellant is what the container of pressurized gas is called. When the pressure hol ...

History

In the 1940s, researchers, originally at Dow's Chemical Physics Lab, led by Ray McIntire, found a way to make foamed

polystyrene Polystyrene (PS) is a synthetic polymer made from monomers of the aromatic hydrocarbon styrene. Polystyrene can be solid or foamed. General-purpose polystyrene is clear, hard, and brittle. It is an inexpensive resin per unit weight. It i ...

. They rediscovered a method first used by Swedish inventor Carl Georg Munters, and obtained an exclusive license to Munters's

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an sufficiency of disclosure, enabling discl ...

in the United States. Dow found ways to adapt Munters's method to make large quantities of

extruded Extrusion is a process used to create objects of a fixed cross-sectional profile by pushing material through a die of the desired cross-section. Its two main advantages over other manufacturing processes are its ability to create very complex ...

polystyrene as a closed cell foam that resists moisture. The patent on this adaptation was filed in 1947.

Uses

Styrofoam has a variety of uses. Styrofoam is composed of 98% air, making it lightweight and buoyant. DuPont produces Styrofoam building materials, including varieties of

sheathing and pipe insulation. The claimed R-value of Styrofoam insulation is approximately 5 °F⋅ft²⋅h/BTU for 1 inch thick sheet. Styrofoam can be used under roads and other structures to prevent soil disturbances due to freezing and thawing. DuPont also produces Styrofoam blocks and other shapes for use by

florist Floristry is the production, commerce, and trade in flowers. It encompasses flower care and handling, floral design and arrangement, merchandising, production, display and flower delivery. Wholesale florists sell bulk flowers and related s ...

s and in craft products. DuPont insulation Styrofoam has a distinctive blue color; Styrofoam for craft applications is available in white and green.

Environmental issues

The EPA and

International Agency for Research on Cancer The International Agency for Research on Cancer (IARC; ) is an intergovernmental agency forming part of the World Health Organization of the United Nations. Its role is to conduct and coordinate research into the causes of cancer. It also cance ...

reported limited evidence that

styrene Styrene is an organic compound with the chemical formula C6H5CH=CH2. Its structure consists of a vinyl group as substituent on benzene. Styrene is a colorless, oily liquid, although aged samples can appear yellowish. The compound evaporates easi ...

carcinogen A carcinogen () is any agent that promotes the development of cancer. Carcinogens can include synthetic chemicals, naturally occurring substances, physical agents such as ionizing and non-ionizing radiation, and biologic agents such as viruse ...

ic for humans and experimental animals, meaning that there is a positive association between exposure and cancer and that causality is credible, but that other explanations cannot be confidently excluded. See also the expansive list of environmental issues of polystyrene, among which it being non-biodegradable.

References

{{Reflist Dow Chemical Company Foams Plastic brands Brand name materials Brands that became generic Building insulation materials Organic polymers Swedish inventions 1941 in technology Products introduced in 1941 American inventions