Styrene monomer is an aromatic hydrocarbon which, under normal conditions, is a clear, colourless, flammable liquid.
The conventional method for producing styrene monomer is the alkylation of benzene with ethylene followed by dehydrogenation to produce styrene monomer. The notable exception to this is the process to co-produce styrene monomer and propylene oxide via the oxidation of propylene by ethylbenzene hydroperoxide, also known as the 'SMPO' process.
Styrene monomer is used to make styrene-based polymers. These, in turn, are used in the manufacture of plastic and rubber products, including polystyrene (PS), expandable polystyrene (EPS), acrylonitrile butadiene styrene (ABS), styrene-acrylonitrile, styrene butadiene rubber (SBR), unsaturated polyester resins, and styrene butadiene latices.
The majority of styrene monomer is used in the production of polystyrene. General purpose, or 'crystal' polystyrene, and high impact polystyrene are used in everyday items such as CD cases, drinks cups, food containers and refrigerator door liners. Expandable polystyrene, a lightweight foam, is used in home insulation, as a packaging material, as padding inside motorcycle crash helmets and car interiors, in bridge construction, and to build film-set scenery.