Polystyrene (PS) plastic is a naturally transparent thermoplastic that is available as both a typical solid plastic as well in the form of a rigid foam material. PS plastic is commonly used in a variety of consumer product applications and is also particularly useful for commercial packaging. Dow Chemical Company invented a proprietary process to make their trademarked and well-known polystyrene foam product “styrofoam” in 1941. The material is somewhat controversial amongst environmental groups because it is slow to biodegrade and is increasingly present as outdoor litter (particularly in the form of foam floating in waterways and the ocean).

The solid plastic form of polystyrene is commonly used in medical device applications like test tubes or petri dishes, or in day-to-day items like the housing on your smoke detectors, the case you used to buy your CDs in, and frequently as a container for foods like yogurt or the red “solo” cup you drink from at a tailgate and/or when you’re losing in a game of beer-pong.

The foam form of polystyrene is used most often as a packing material. You have probably unpacked a custom styrofoam housing if you’ve ever bought a new television, or a significant piece of new equipment like a Miter saw. Similarly, you’re probably familiar with styrofoam packing “peanuts” used as filler for miscellaneous small items being shipped. Styrofoam is also used for “to-go” containers and disposable tableware from many restaurants.