Polystyrene

Polystyrene (PS) /ˌpɒliˈstaɪriːn/ is a synthetic <a href="/facts/Polymer/eF32E50K">polymer</a> made from monomers of the <a href="/facts/Aromatic_hydrocarbon/3EXq8Tgf">aromatic</a> hydrocarbon <a href="/facts/Styrene/B8uXm78L">styrene</a>. Polystyrene can be solid or <a href="/facts/Foam/kGrXWWcb">foamed</a>. General-purpose polystyrene is clear, hard, and brittle. It is an inexpensive resin per unit weight. It is a poor barrier to air and water vapor and has a relatively low melting point. Polystyrene is one of the most widely used <a href="/facts/Plastic/Kla5QItn">plastics</a>, with the scale of its production being several million tonnes per year. Polystyrene is naturally <a href="/facts/Transparency_(optics)/PRryNNW6">transparent</a>, but can be colored with colorants. Uses include protective packaging (such as <a href="/facts/Foam_peanut/V4eRqbDB">packing peanuts</a> and <a href="/facts/Optical_disc/vjVDB1GH">optical disc</a> <a href="/facts/Optical_disc_packaging/uzIJFGka">jewel cases</a>), containers, lids, bottles, trays, tumblers, <a href="/facts/Disposable/LTgTEmRG">disposable</a> <a href="/facts/Cutlery/LfV0Pwzv">cutlery</a>, in the making of models, and as an alternative material for <a href="/facts/Phonograph_record/ccuFV9Af">phonograph records</a>.
As a <a href="/facts/Thermoplastic/5KJB8dwN">thermoplastic</a> polymer, polystyrene is in a solid (glassy) state at room temperature but flows if heated above about 100 °C, its <a href="/facts/Glass_transition_temperature/yVl3QzsT">glass transition temperature</a>. It becomes rigid again when cooled. This temperature behaviour is exploited for <a href="/facts/Extrusion/wM2kJ6wc">extrusion</a> (as in <a href="/facts/Styrofoam/ULtGBPUN">Styrofoam</a>) and also for <a href="/facts/Molding_(process)/1GkAeyCx">molding</a> and <a href="/facts/Vacuum_forming/1QV6paqL">vacuum forming</a>, since it can be cast into molds with fine detail. The temperatures behavior can be controlled by photocrosslinking.
Under <a href="/facts/ASTM/xzdCexYJ">ASTM</a> standards, polystyrene is regarded as not <a href="/facts/Biodegradable/d1UW4dfR">biodegradable</a>. It is accumulating as a form of <a href="/facts/Litter/KD9knQuN">litter</a> in the outside <a href="/facts/Environment_(biophysical)/PNzMrGrz">environment</a>, particularly along shores and waterways, especially in its foam form, and in the Pacific Ocean.

Polystyrene open-in-new

Polystyrene