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Material World
Compound · C8H8

Styrene

A benzene ring with a handle, and the monomer behind polystyrene, ABS, synthetic rubber and most fibreglass resin.

Styrene is a benzene ring carrying a vinyl group, and it polymerises readily enough that it does so on its own if left warm — commercial styrene is shipped with an inhibitor for exactly that reason, and a tank that loses its inhibitor and its cooling is a serious industrial hazard.

The aromatic ring is what it contributes. In polystyrene the rings make a rigid, glass-clear, brittle solid; copolymerised with butadiene they make a rubber tough enough for tyres; grafted onto a rubber phase with acrylonitrile they make ABS.

Processing

Made by alkylating benzene with ethylene to give ethylbenzene, then dehydrogenating that over an iron oxide catalyst at around 600 °C. The second step is strongly endothermic and equilibrium-limited, so it runs with large volumes of superheated steam — which is where a substantial part of the energy cost of every styrenic polymer sits.

Uses

Polystyrene, expanded polystyrene, ABS, styrene-butadiene rubber for tyres, styrene-butadiene latex for paper coating and carpet backing, and unsaturated polyester resin — which is the matrix of most glass-fibre composites, and the reason a boatyard smells the way it does.

History

Distilled from storax resin in 1839 by Eduard Simon, who recorded that his liquid thickened to a jelly over time without understanding why; the polymer was made before anyone had the concept of a macromolecule to describe it.

Industrial production dates from the 1930s, and synthetic styrene-butadiene rubber from the American and German wartime programmes, both prompted by natural rubber supply being cut off.

Medium confidence Weak evidence

How we know: checked recently · only one source, so there is nothing to cross-check it against · stated directly by the source.

How this connects

Where a connection has been confirmed by an outside reference, that reference is named beside it.

is sourced from

  • Ethylene — compound · via ethylbenzene: ethylene alkylates benzene, and the product is dehydrogenated

is an input to

  • Polymerisation — process · into polystyrene, into ABS with acrylonitrile and butadiene, and into SBR with butadiene

is a source for

  • Polystyrene — material · straightforward addition polymerisation
  • ABS — material · one of the three monomers, supplying rigidity and gloss to the continuous phase
  • Styrene-butadiene rubber — material · the co-monomer with butadiene, and the ratio between them is what tunes grip against rolling resistance

contains

  • Carbon — element · eight, six of them in the benzene ring that stiffens every polymer it goes into
  • Hydrogen — element · eight

is produced by

  • Steam cracking — process · by way of ethylbenzene, which is ethylene and benzene joined and then dehydrogenated

Sources

  • Material World
    Our own writing
  • Wikidata
    Wikimedia Foundation · Creative Commons CC0 1.0 Universal (public domain dedication)

Questions this page answers

Where it comes from, and what it becomes

Follow Styrene back to what it starts as, and forward into what it becomes. Each step is a documented one — a real route material takes, not a chain of inference.

Upstream — what it comes from

  • Styrene → is sourced from (via ethylbenzene: ethylene alkylates benzene, and the product is dehydrogenated) → Ethylene → is produced by (the principal product, and the largest-tonnage organic chemical made anywhere) → Steam cracking → takes as input (the European and Asian cracker feed; North American crackers mostly run on ethane from natural gas instead, and make a different product slate as a result) → Naphtha → is sourced from (the fraction boiling between about 30 and 200 °C, separated by distillation rather than made) → Crude oil
  • Styrene → is produced by (by way of ethylbenzene, which is ethylene and benzene joined and then dehydrogenated) → Steam cracking → takes as input (the European and Asian cracker feed; North American crackers mostly run on ethane from natural gas instead, and make a different product slate as a result) → Naphtha → is sourced from (the fraction boiling between about 30 and 200 °C, separated by distillation rather than made) → Crude oil

Downstream — what it becomes

  • Styrene → is a source for (one of the three monomers, supplying rigidity and gloss to the continuous phase) → ABS → is used to make (not the device but the package and the board hardware around it — the plastics are most of what a reader actually handles) → Transistor → is used in (the component every other modern technology is assembled from, and one nobody ever sees) → Electronics manufacture → is associated with (and the supply chain it produced is the deepest and most concentrated in the world economy) → The semiconductor era complete chain
  • Styrene → is an input to (into polystyrene, into ABS with acrylonitrile and butadiene, and into SBR with butadiene) → Polymerisation → produces (from ethylene; chain length and branching decide whether it is a milk bottle or a fibre) → Polyethylene → is associated with (its first significant use was radar cable insulation, and its existence was classified) → The wartime materials programmes complete chain
  • Styrene → is a source for (the co-monomer with butadiene, and the ratio between them is what tunes grip against rolling resistance) → Styrene-butadiene rubber → is associated with (American production went from almost nothing to hundreds of thousands of tonnes a year in three years, with patents pooled by government direction) → The wartime materials programmes complete chain
  • Styrene → is a source for (straightforward addition polymerisation) → Polystyrene → is used as (as expanded foam for protective packing, and formerly for food service until a great many jurisdictions banned it) → Packaging
  • Styrene → is a source for (straightforward addition polymerisation) → Polystyrene → is an input to (cheap rigid mouldings, and the reason so much disposable product was polystyrene before it was polypropylene) → Injection moulding
  • Styrene → is a source for (straightforward addition polymerisation) → Polystyrene → is used as (as expanded and extruded foam board — the cheapest insulation per unit of thermal resistance, and combustible, which is where the regulatory argument sits) → Thermal insulation

These are the most distinct paths onward. Styrene ends up in others besides.