Styrene Monomer
The monomer behind polystyrene, ABS, SAN and SBR rubber — one of the highest-volume monomers in the petrochemical industry.
Chelora Chemicals supplies inhibitor-stabilised styrene monomer to polymer and rubber producers worldwide, with full documentation on every consignment.
Product identity
- CAS Number
- 100-42-5
- IUPAC name
- Ethenylbenzene
- Molecular formula
- C₈H₈
- Molecular weight
- 104.15 g/mol
- Boiling point
- 145 °C
- Melting point
- -30.6 °C
- UN Number
- UN 2055
- HS Code
- 2902 50
Note: Styrene monomer is shipped inhibitor-stabilised (typically with TBC) and is temperature-sensitive in storage. Confirm requirements with your regulatory affairs team.
What Styrene is used for
Styrene Monomer (SM) is a colourless to pale yellow, flammable liquid with a characteristic sweet, penetrating odour that becomes unpleasant at high concentration. It is produced almost entirely by the catalytic dehydrogenation of ethylbenzene, with a smaller share made by the co-production (POSM) route alongside propylene oxide.
Styrene's largest use is as the monomer for polystyrene — general-purpose and high-impact grades for packaging, disposable goods, insulation foam and appliance housings. It is also copolymerised into ABS and SAN engineering resins, styrene-butadiene rubber (SBR) for tyres, and unsaturated polyester resins, where it serves as the reactive diluent and crosslinking agent for fibreglass-reinforced composites.
Where it sits in the petrochemical value chain
- Ethylbenzene the feedstock, dehydrogenated to styrene. See that page.
- Styrene Monomer (this product) the monomer for the polymer and rubber chains below.
- Polystyrene / ABS / SAN / SBR downstream polymers built on this monomer. See Polystyrene.
Handling character
Styrene is flammable, harmful by inhalation, and a suspected carcinogen, and polymerises exothermically if the inhibitor is depleted. Full hazard detail is in the Safety section below.
| Parameter | Typical value |
|---|---|
| Appearance | Colourless to pale yellow liquid |
| Assay | 99.6% min (polymer grade) |
| Polymer content | < 50 ppm (typical) |
| TBC inhibitor content | Within producer specification (typ. 10-15 ppm) |
Important: the figures above are indicative of commercial material and are offered for planning only. The batch certificate of analysis is the governing document.
| Property | Value |
|---|---|
| Physical state | Colourless to pale yellow, flammable liquid |
| Boiling point | 145 °C |
| Melting point | -30.6 °C |
| Density | 0.906 g/cm³ |
| Water solubility | Low (~0.31 g/L) |
| Flash point | 31 °C (flammable) |
Physical constants compiled from public reference data for CAS 100-42-5 and rounded for readability. Treat them as orientation, not as a specification.
Where our customers put Styrene to work
The monomer behind rigid packaging, foam insulation, engineering plastics and tyre rubber.
Polystyrene (GPPS/HIPS)
Polymerised into general-purpose and high-impact polystyrene for packaging, disposables and housings.
- Polymer-grade specification
- Inhibited bulk & drum supply
- Technical desk review on request
Expandable polystyrene (EPS)
Polymerised with a blowing agent into EPS beads for insulation and protective packaging foam.
- Industrial-grade specification
- Documented batch traceability
- Contract & spot supply
ABS & SAN resins
Copolymerised with butadiene and acrylonitrile (ABS) or acrylonitrile alone (SAN) for engineering plastics.
- Full analytical documentation available
- Retained sample held against the lot
Styrene-butadiene rubber (SBR)
Copolymerised with butadiene into SBR, the dominant rubber for tyre tread compounds.
- Documented batch traceability
- Technical desk review on request
Unsaturated polyester resins
Used as the reactive diluent and crosslinker in UPR for fibreglass-reinforced composites.
- Research & process-scale quantities
- Full documentation supplied
Contract & scheduled supply
Polymer and rubber plants running continuous consumption are supported with scheduled bulk delivery.
- Annual contracts with scheduled call-off
- Price held across the contract period
- Second source held in reserve
How we supply Styrene Monomer
Chelora Chemicals is a supplier and sourcing partner, not a manufacturer. Styrene's polymerisation sensitivity makes inhibitor level and temperature-controlled logistics critical — that shapes how we manage this line.
We place your order with whichever qualified producer best matches your required grade, your price point and your delivery window, and confirm your jurisdiction's import requirements before booking.
We keep a second qualified source on this line, so a single-plant disruption never becomes your production problem.
- Inhibitor and polymer content confirmed before we quote. Consistency matters to downstream polystyrene, ABS and SBR polymerisation.
- UN 2055 documentation managed end to end. Classification, labelling and carrier compliance confirmed before booking.
- Temperature-controlled logistics arranged where needed. Styrene's polymerisation sensitivity rises with temperature, so cool-chain handling protects quality.
- Batch traceability to the producing plant. Full chain of custody documentation on request.
- Export machinery handled in-house. Classification, approved packing, labelling, freight booking and customs paperwork are ours to manage.
- Polymer-grade material sourced to your process. Matched precisely to your polystyrene, ABS, SBR or UPR specification.
Packed the way your plant receives it
Drum, tote or bulk tank — tell us your preferred format and we will quote and classify to it.
200-210 litre drums
Steel drums, inhibitor-stabilised, for smaller-volume orders and trial quantities.
~1,000 litre totes
Returnable or one-way IBC totes sized for mid-volume converter orders.
Temperature-controlled bulk shipment
ISO tank or flexi-tank bulk shipment, temperature-managed, for continuous-consumption polymer and rubber plants.
Incoterms to suit you
Quoted on the Incoterm your purchasing team works to, with documentation filed before booking.
Trial / sample quantities
Small packs dispatched for process trials before a commercial order is placed.
Contracted call-off supply
We hold contracted tonnage and release it against your consumption calendar.
Flammable & reactive — handle accordingly
Styrene is flammable, harmful if inhaled, a suspected carcinogen, and can polymerise exothermically if the inhibitor is depleted or the material overheats. The summary below is orientation only — the safety data sheet supplied with your specific batch is the authoritative document.
Classified hazards
H226Flammable liquid and vapour.H332Harmful if inhaled.H315+H319+H373Causes skin and eye irritation; causes damage to organs (hearing) through prolonged or repeated exposure.
Never allow the inhibitor to deplete or temperature to rise uncontrolled. Uncontrolled polymerisation can be violent; always read the SDS issued with your specific batch and monitor storage temperature.
Storage
Store inhibited material in tightly closed, temperature-controlled containers (typically below 20-30 °C) away from heat, sunlight, oxidisers and peroxide-forming conditions, with adequate dissolved oxygen maintained.
Handling
Use chemical-resistant gloves, eye protection and adequate ventilation for liquid transfer. Avoid inhalation and prolonged skin contact; never store without adequate inhibitor and headspace oxygen.
Transport
Shipped as UN 2055 (Styrene monomer, stabilized), a flammable liquid. We confirm and document exact classification for your specific shipment and destination.
Every batch, documented
We verify documentation before dispatch so there are no surprises at your incoming-goods bench.
Specification agreed
Assay, polymer content and inhibitor level confirmed against your process requirement before order placement.
Producer batch testing
The producing plant tests each batch against the agreed specification before release.
Documentation review
COA, SDS and transport paperwork checked by our desk before the shipment is booked.
Traceable dispatch
Each shipment is traceable to its producing batch, with full chain-of-custody records on request.
How Styrene is made
Styrene is produced industrially mainly by the catalytic dehydrogenation of ethylbenzene over iron-oxide-based catalysts at high temperature, with hydrogen recovered as a co-product. A secondary route, the POSM (propylene oxide/styrene monomer) process, co-produces styrene alongside propylene oxide via ethylbenzene hydroperoxide.
We do not publish operating process parameters here; this is background only. Full technical documentation accompanies every shipment, and any process-specific detail you need is best confirmed directly with our technical desk.
| Chemical family | Aromatic vinyl monomer |
|---|---|
| Functional groups | Vinyl group conjugated with an aromatic ring |
| Reactivity | Free-radical, anionic and coordination (co)polymerisation; requires inhibitor during storage |
| Related compounds | Ethylbenzene (feedstock), Polystyrene, ABS, SBR (downstream) |
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Styrene Monomer, answered
What is Styrene Monomer used for?
How is Styrene Monomer made?
Is Styrene Monomer hazardous?
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