Polystyrene (PS) / ˌpɒlistaɪriːn / a synthetic aromatic polymer made of styrene monomer. Polystyrene can be solid or foamed. General purpose polystyrene is clear, hard, and somewhat fragile. This is the cost per unit weight of resin. This is a rather poor oxygen barrier and water vapor and has a relatively low melting point. Polystyrene is one of the most widely used plastics, the scale of production into several billion kilograms per year. Polystyrene can be naturally transparent, but can be colored with dyes. Including the use of protective packaging (such as packing peanuts and CD and DVD case), container (such as "clamshell"), lids, bottles, trays, cups and disposable cutlery.
As a thermoplastic polymer, polystyrene is in the (glass) solid state at room temperature, but flows if heated above 100 ° C, the glass transition temperature. This becomes rigid again when cooled. Behavior is used for extrusion temperatures (such as in a styrofoam) and also for molding and vacuum, because it can be cast into molds with fine detail.
Polystyrene is very slow to decompose and therefore the focus of controversy among environmentalists. It is more abundant as a form of litter in the outdoor environment, particularly along the coasts and waterways, particularly in the form of foam, and also in increasing numbers in the Pacific Ocean.