Polystyrene material properties make it one of the most heavily-manufactured and utilized plastics in the world as of 2011. This includes the primary fact that the polystyrene structure is a thermoplastic, which means that it becomes soft and pliable under a temperature of about 212° Fahrenheit (100° Celsius) without degrading its chemical bonds, allowing the plastic to be shaped into many useful forms and products. Since it is also a naturally clear plastic compound derived from petroleum, it can be given many different permanent colors by mixing pigments into it when it is in a liquid state, which allows it to be used for everything from costume jewelry to plastic lettering and toys to machine parts.
The nature of polystyrene properties were first identified in 1839 by a German named Eduard Simon who refined it from natural resin taken from the Sweetgum, or Liquidambar orientalis, tree. The plastic was not widely manufactured until almost a century later, however, with German companies dominating the market in the early 1930s and US firms getting involved by 1937. Since the expanded polystyrene properties for most products include that the plastic is fairly rigid, it is outsold globally by a softer though related plastic known as polyethylene.
Both polystyrene and polyethylene plastics are in the class of compounds known as vinyl polymers. A vinyl polymer displays polystyrene chemistry with the connection of long chains of small vinyl monomer compounds which are individual carbon atoms double bonded to two hydrogen atoms. While polyethylene is considered to be the most simple of vinyl polymers, others in the group share many polystyrene properties, such as polypropylene and polyvinyl chloride (PVC).
Polystyrene foam properties, where air or carbon dioxide can be mixed into the plastic during heating, also make it an ideal packaging and insulating material for oddly-shaped merchandise, which it can be molded around to prevent breakage during shipment. Polystyrene chemistry also makes the compound inert for the storage of many industrial chemicals and foods at normal room temperature, but it is not designed to contain heated materials as it can release carcinogenic styrene compounds into food in the process. These polystyrene properties have led to its most visible use in the consumer market as the material that has come to be known as styrofoam.
The thermoplastic nature of the polystyrene chemical compound has resulted in its use for many types of food containers and plastic parts like eating utensils that are considered to be disposable items. This is because polystyrene properties include that it can be readily recycled by compacting, sterilizing, and melting it down to reform it into other products. It is not a biodegradable product, however, and can endure exposure to sunlight and the natural environment for hundreds of years before it begins to naturally break down.