• Suspension polymerization (with organic peroxides)
• Bulk polymerization (with organic peroxides or heat)
• Emulsion polymerization (with organic peroxides)

For three different production processes, organic peroxides are used such as Dialkyl peroxides, Diacyl peroxides, Peroxide carbonates, Peroxyketales, Hydroperoxide and aromatic or non- aromatic Peresters.

Expanded Polystyrene (EPS) is produced with bulk operation as well as suspension. In the case of suspension polymerization, during polymerization reaction, the inflator substance (e.g., Pentane) can be added. In the case of bulk operation, using an extruder of blowing, blowing material should be added after polymerization reaction with a second production process.