Styrene (also known as STY, styrene monomer, vinyl benzene, phenylethylene, styrol, styrole, styrolene, cinnamene, styron, and cinnamol) is a clear, colourless to yellow, oily liquid with a sweet smell. It has the formula C8H8 and it evaporates easily and is also flammable. Styrene is an essential component in the making of 1000’s of everyday products as it provides strength and flexibility whilst also being lightweight.
Styrene occurs naturally in the environment and is found in many foods such as coffee, strawberries, and cinnamon. It was named after styrax trees from whose sap (benzonin resin) it can be extracted. However, it is now derived from petroleum and natural gas by-products with styrene most commonly produced by the catalytic dehydrogenation of ethylbenzene. Commercially, styrene can also be co-produced with propylene oxide, in a process known as POSM or SM/PO.
Styrene is an important monomer in the petrochemical industry with world production at a level of approximately 20 million tonnes per year.
Storage and distribution
Styrene is stored in stainless steel, zinc, and/or mild steel tanks or drums and can be transported by tank car and trucks. It has a specific gravity of 0.91 and a flash point of 31° C and is thus highly flammable. It should therefore be stored in a cool, dry, well-ventilated area that is free from the risk of ignition. Styrene is classified as packing group III, hazard class 3, and should be labelled as an irritant.
Styrene is an adaptable synthetic chemical and it is used in the manufacture of materials which are then used to produce an amazing variety of products across a wide range of industries. The most recognisable of the styrene-based materials is polystyrene, with nearly 65 % of all styrene used to produce this. Polystyrene is used in a huge range of everyday products and can be found in packaging, toys, recreational equipment, consumer electronics and safety helmets, to name but a few.
Other materials produced include acrylonitrile-butadiene styrene (ABS) and styrene-acrylonitrile (SAN) resins and account for approximately 16 % of styrene consumption. ABS is a thermoplastic resin that is used in the automobile and electronics industry, while SAN is a co-polymer plastic that is used in a range of consumer goods, packaging, and automotive applications.
Styrene is also utilised in the manufacture of styrene-butadiene rubber (SBR) elastomers and latexes, and accounts for approximately 6% of consumption. SBR is used in car tyres, and belts and hoses for machinery, as well as in household items such as toys, sponges and floor tiles.
Unsaturated polyester resin (UPR), better known as fibreglass, is another material based on styrene and this also accounts for approximately 6% of styrene consumption.
Historically, growth in the use of styrene has been good although this growth has slowed with the global economic downturn.