Forms Produced :

Polystyrene is usually injection molded, vacuum formed, or extruded, while extended polystyrene is either extruded or molded in a specific process.
Polystyrene copolymers are also produced; these have one or more other monomers in addition to styrene.
Recently the expanded polystyrene composites with cellulose and starch have also been produced. Polystyrene is used in some polymer-bonded explosives (PBX).