Styrofoam is a type of polystyrene (a type of plastic) foam that's light yet strong. It’s often used to make take-out coffee cups and packing materials.
Styrofoam — which is usually capitalized, because it's a proprietary name — is a type of lightweight, durable foam. If you've ever gotten a package full of little packing peanuts, they were probably made of Styrofoam. Styrofoam is controversial, so a lot of places stopped using it. Since it doesn't biodegrade, Styrofoam products are considered harmful to the environment.
Polystyrene is a versatile plastic used to make a wide variety of consumer products. As a hard, solid plastic, it is often used in products that require clarity, such as food packaging and laboratory ware. When combined with various colorants, additives or other plastics, polystyrene is used to make appliances, electronics, automobile parts, toys, gardening pots and equipment and more.
Polystyrene also is made into a foam material, called expanded polystyrene (EPS) or extruded polystyrene (XPS), which is valued for its insulating and cushioning properties. Foam polystyrene can be more than 95 percent air and is widely used to make home and appliance insulation, lightweight protective packaging, surfboards, foodservice and food packaging, automobile parts, roadway and roadbank stabilization systems and more.
Polystyrene is made by stringing together, or polymerizing, styrene, a building-block chemical used in the manufacture of many products. Styrene also occurs naturally in foods such as strawberries, cinnamon, coffee and beef.