Styrene, CH =CH–C H , polymerizes readily to form polystyrene (PS), a hard, highly transparent 2 6 5
polymer. The molecular structure is similar to that of polypropylene, but with the methyl groups of polypropylene
replaced by phenyl groups (–C H ). A large portion of production goes into packaging. The thin, 6 5
rigid, transparent containers in which fresh foods, such as salads, are packaged are made from polystyrene.
Polystyrene is readily foamed or formed into beads. These foams and beads are excellent thermal insulators and are
used to produce home insulation and containers for hot foods. Styrofoam is a trade name for foamed polystyrene.
When rubber is dissolved in styrene before it is polymerized, the polystyrene produced is much more impact resistant.
This type of polystyrene is used extensively in home appliances, such as the interior of refrigerators and air conditioner
housing. [For more information about this polymer, see Chemical Demonstrations: A Handbook for Teachers of
Chemistry, by Bassam Z. Shakhashiri, Volume 1 (1983)