Polystyrene
Desirable properties such as good thermal and electrical insulation, resistance to acids, alkalis, oils and alcohols in addition to being lightweight and flexibility, makes polystyrene products a popular and economic choice for a broad array of industries. Packaging, building, construction and architectural design make frequent use of this material. Furthermore, polystyrene is chemically non-reactive, making its use popular in food, medical, biomedical and pharmaceutical industries as well as applications involving the storage of volatile chemicals. Products produced for such uses are often sterilized by irradiation or an ethylene oxide treatment. Electronic housings, compact discs, cutlery, beakers, insulating panels, food trays, packaging products and window panels are just a few of the myriad polystyrene products available to accommodate the broad spectrum of industrial, commercial and residential use. A
thermoplastic, PS is pliable when heated and rigid when cold allowing it to be easily recycled and remolded numerous times. As it is non-biodegradable, diligent recycling is essential to diminishing the environmental impact of this
plastic material.
The many uses of polystyrene all begin with the same process of joining monomers to create the plastic polymers. Classified as a liquid hydrocarbon, PS is composed of the elements hydrogen and carbon. Through the free-radical polymerization of petroleum or the derivative phenylethene (another name for styrene), and using benzoyl peroxide as the initiator, these hydrocarbon monomers form covalent bonds with phenol groups to create polystyrene. Beyond this point polystyrene can be manufactured in a number of different ways. The most recognizable pre-form of polystyrene is the trade marked extruded foam, Styrofoam. Also available in expanded foam, moldable solids or viscous fluids, polystyrene is supplied to hundreds of different industries in the most applicable pre-form. Injection molding, casting, extrusion and stamping are used to manufacture products from this dimensionally stable material. Stock forms produced by these techniques may be used as the finished product or for further processing. These include
plastic rods,
plastic sheets,
plastic films, pipes, tubes, plates and more. In solid form, this is a colorless, glass-like rigid material. Polystyrene softens just above 100 degrees Celsius and becomes viscous at 185 degrees Celsius. Different fillers can be added to molten polystyrene during processing to alter porosity, strength, flexibility and thermal capabilities.
