Expanded Polystyrene
Expanded Polystyrene, sometimes referred to as EPS, is a type of plastic foam. Expanded polystyrene is produced from unprocessed, solid beads of polystyrene called expandable polystyrene. These beads undergo a process whereby they are expanded to approximately 40 times their original size using gas as a blowing agent. The beads are heated with steam, which causes the gas to boil, forming a lattice of closed cells. As this material then cools, the gas re-liquefies and leaves a partial vacuum inside each bead, which is subsequently placed in a holding tank for twelve hours to allow the pressures to equalise. The beads are then reheated with steam while in a mould, causing them to expand again to the desired shape. The final product is generally white in colour.
Expanded Polystyrene Foam
Expanded polystyrene has a large number of applications due to the qualities which it possesses. The most important quality of EPS is its excellent thermal performance due to its tight cellular structure, which allows only small amounts of heat to pass through it. Another expanded polystyrene property is its lightness and its ability to support many times its own weight in water. Furthermore, EPS is incredibly cost effective to produce. In the case of disposable cups, for example, a manufacturer would use much less energy in the production of polystyrene cups than they would in producing paper cups. Similarly, the potential for waste generated is much lower, as the amount of ash produced when expanded polystyrene is burned is comparatively low. Expanded polystyrene foam is also completely recyclable, and in cases where it is not recycled, it can be deposited safely in landfills as it is inert chemically. Expanded polystyrene density is very low, which allows it to be used in a wide range of applications.
Expanded Polystyrene Board
The qualities of expanded polystyrene make it ideal for use as an insulator. Expanded polystyrene board is frequently used as an insulator in the interior of masonry basement walls, and larger quantities of EPS can be used as underlay for roads, providing a cheap and environmentally sound alternative to other materials. EPS can also be used in cars as a safety precaution. Dashboards made of EPS are designed to collapse on impact, limiting injury to the passengers.
The low expanded polystyrene density makes it an attractive material for use in music studios as an efficient and low cost way to sound proof a room. This same concept can be applied to building construction, using layers of expanded polystyrene board between floors to reduce the sound of people walking around. Its low density coupled with its imperviousness to water also make it practical for usage in floatation devices.
Expanded Polystyrene Packaging
Lastly, expanded polystyrene properties make it useful in the food packaging industry. The ability of EPS to retain heat while remaining light and easy to dispose of make it the popular choice for takeaway meals, and it is also for similar reasons used in sandwich packets. Furthermore, the cheapness of its production lends itself well to be used by expanded polystyrene manufacturers in the making of egg cartons.