This temperature behaviour is exploited for extrusion (as in Styrofoam) and also for molding and vacuum forming, since it can be cast into molds with fine detail. Īs a thermoplastic polymer, polystyrene is in a solid (glassy) state at room temperature but flows if heated above about 100 ☌, its glass transition temperature.

Uses include protective packaging (such as packing peanuts and in the jewel cases used for storage of optical discs such as CDs and occasionally DVDs), containers, lids, bottles, trays, tumblers, disposable cutlery, in the making of models, and as an alternative material for phonograph records. Polystyrene can be naturally transparent, but can be colored with colorants.

Polystyrene is one of the most widely used plastics, the scale of its production being several million tonnes per year. It is a poor barrier to oxygen and water vapour and has a relatively low melting point. It is an inexpensive resin per unit weight. General-purpose polystyrene is clear, hard, and brittle. Polystyrene ( PS) / ˌ p ɒ l i ˈ s t aɪ r iː n/ is a synthetic polymer made from monomers of the aromatic hydrocarbon styrene. Bottom of a vacuum-formed cup fine details such as the glass and fork food contact materials symbol and the resin identification code symbol are easily molded

Crack film impact transitions