Polystyrene resin is a thermoplastic polymer produced from styrene, a petroleum derived liquid hydrocarbon. The resin possesses low softening temperatures, good wear characteristics, a high refractive index, and excellent electrical insulation properties. Polystyrene resin is used in a wide range of manufacturing processes such as injection molding, sheet and film extrusion, and expanded foam extrusion. Items produced from these resins are found in abundance in a diverse range of environments. The storage and eventual disposal of resin products requires considerable care and planning due to substantial fire hazards and extremely low biodegradability characteristics.
Polymer resins have become an integral part of virtually every area of life and can be found in a huge array of domestic and industrial products. One of the more prevalent of these plastics is polystyrene resin. This tough, transparent thermoplastic possesses a variety of attractive qualities which have made it one of the most widely used polymer resins ever. These characteristics include low costs, good wear properties, low working temperatures, excellent insulating qualities, and a high electrical insulation rating. The resin's low transition temperature make it ideal for production processes such as thermoforming, injection molding, and various extrusion processes.
When it comes to range of uses, it is almost impossible to to find an area where these resin products are not used. Domestic products range from plastic cutlery to refrigerator door liners and include items such as toys, insulating panels, disposable razors, appliance casings, and furniture components. The ubiquitous Styrofoam cup, molded packaging inserts, and peanuts are all polystyrene resin products. Most CD and DVD cases also consist of combinations of general purpose and high impact polystyrene resin.
In industrial settings the resins excellent electrical insulation properties make it a regular motor and coil encapsulation material. These resins are also a common component of power tool casings, hand tool handles, tool boxes, and construction sheets. The medical and pharmaceutical industries also use a wide range of these resin products. Items such as Petri dishes, test tubes, microplates, and laboratory containers are all produced from polystyrene resin using sterile molding techniques. The resin is even used in military ordinance production as a binder for RDX TNT explosives, an additive of napalm, and one of the components of many hydrogen bomb variants.
For all their widespread uses and positive attributes, these resins have two negative characteristics. The first is the fire risk involved. Polystyrene products, particularly expanded foam items, are easily ignited, burn with a very hot flame, and exude large amounts of toxic fumes and soot. For this reason, the use of polystyrene foams as insulation and the storage and transportation of polystyrene products require considerable care.
The second disadvantage of polystyrene resin products is their longevity after disposal. Polystyrene products do not biodegrade for several centuries; film and foam items, among others, float and are easily blown around by the wind. A disturbing proportion of land and waterborne pollution is made up of polystyrene products which makes their responsible disposal a critical consideration.