What is Expanded Polystyrene?
Expanded polystyrene (EPS) foam is the most common foam cut for architectural shapes, structural insulated panel systems (SIPS), insulated concrete forms (ICF), precast concrete molds and models, theming, and sign making. EPS is technically a plastic. The word ‘plastic’ comes from Greek plastikos, which means capable of being molded. The freedom to be creative with custom designs is a major reason why we find EPS so valuable today. It is also interesting to know that EPS foam is the same material (polystyrene) used to make hard shell CD cases and other household products. To find polystyrene in everyday products, look for recycling number ‘6’. • EPS Characteristics • Light Weight: Typically 1 lb. – 2 lbs. / cubic foot • Highly Insulative: Because there is no thermal drift, 1 inch provides lifetime R-3.6 to R-4.2 values (depending on density) • Environmentally Friendly: EPS has always been CFC- and HCFC-Free • Manufactured Locally: Hundreds of plants throughout the world • Chemical Prop
Expanded polystyrene is a plastic foam material that has certain desirable properties because of its structure. It is extraordinarily light and buoyant, and a good insulator against heat and sound. It can be used as a building material or a design element, and can be molded into many shapes for a number of household uses as well. In most cases, expanded polystyrene foam is white and is composed of small, interconnected beads. It is made by combining the chemicals ethylene and benzene, to make a compound known as styrene. The styrene is then treated with other chemicals which cause the styrene molecules to polymerize, or to group together in long chains. This reaction is only allowed to proceed to a certain point, and is then stopped. The resulting beads are allowed to cool and are then cleaned. After formation and cleaning, the beads must be expanded, which happens in three main stages. First, the beads are heated with hot air or steam until their density is three percent of its origin
