Specialty Additives Available — Bulk Only

Styrene (Vinylbenzene)

CAS 100-42-5 · Formula C8H8 · MW 104.15 g/mol

The aromatic monomer feeding polystyrene, styrenics, and polyester composites. It is polymerized to polystyrene, copolymerized into SBR rubber, ABS, and SAN resins, and used as the crosslinking monomer in unsaturated polyester composites.

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UN Number
UN 2055
Hazard Class
Class 3
HS Code
2902.50
At a Glance
Material Family
Specialty Additives
Record Type
Pure compound
Primary Role
Solvency · Synthesis Intermediate
Functional Roles
Solvency Synthesis Intermediate
INCI Name
STYRENE
CosIng Functions
SOLVENT
Industries Served
Coatings & Construction Plastics & Polymers
Applications & Use Cases
  • ▸ Polystyrene: Monomer for polystyrene plastics.
  • ▸ Synthetic rubber: Comonomer in styrene-butadiene rubber (SBR).
  • ▸ Engineering resins: Component of ABS and SAN.
  • ▸ Composites: Crosslinking monomer in unsaturated polyester (FRP).
  • ▸ Ion-exchange resins: Intermediate.
Physical Properties
Physical Description
Styrene monomer, stabilized appears as a clear colorless to dark liquid with an aromatic odor. Vapors heavier than air and irritating to the eyes and mucous membranes. Subject to polymerization. If the polymerization takes place inside a closed container, the container may rupture violently. Less dense than water and insoluble in water. Used to make plastics, paints, and synthetic rubber.
Color/Form
Colorless to yellowish, oily liquid
Odor
If pure, sweet and pleasant, but usually contains aldehydes that have a typical penetrating smell, sharp, sweet, and unpleasant.
Boiling Point
293 to 295 °F at 760 mmHg (NTP, 1992)
Melting Point
Latent heat of fusion: 10.95 kJ/mole (at melting point); Latent heat of sublimation: 43.9 kJ/mole (25 °C); Heat of formation: 103.8 kJ/mole (25 °C); Ionization potential: 8.42 eV
Flash Point
The Guide from the Emergency Response Guidebook is for "Styrene monomer, stabilized." 34 °C
Solubility
Soluble in ethanol, ether, and acetone; miscible with benzene; slightly soluble in carbon tetrachloride
Density
Percent in saturated air at 760 mm Hg & 15 °C: 0.57; density of saturated vapor-air mixture at 760 mm Hg & 15 °C: 1.02 (Air = 1)
Vapor Density
Relative vapor density (air = 1): 3.6
Vapor Pressure
4.3 mmHg at 59 °F ; 9.5 mmHg at 86 °F; 10 mmHg at 95 °F (NTP, 1992)
LogP
log Kow = 2.95
Henry's Law Constant
Henry's Law constant = 0.00275 atm cu m/mole at 25 °C
Stability/Shelf Life
... Styrene is stabilized by a polymerization inhibitor (often tertbutylcatechol). If this is not present in adequate concn, styrene can polymerize and explode its container. The polymerization is also speeded up by temperatures above 66 °C (150 °F).
Autoignition Temperature
914 °F (USCG, 1999)
Decomposition
Hazardous decomposition products formed under fire conditions - Carbon oxides.
Viscosity
0.696 cP at 25 °C
Corrosivity
Styrene will corrode copper and copper alloys
Heat Of Combustion
-4,395.63 kJ/mol at 25 °C
Heat Of Vaporization
10.50 kcal/mol at 25 °C
Surface Tension
32.3 dynes/cm at 20 °C
Ionization Potential
8.40 eV
Polymerization
Usually contains inhibitors to prevent polymerization. Polymerization may be caused by elevated temperature, oxidizers, peroxides, or sunlight. Uninhibited monomer vapor may form polymer in vents and other confined spaces. /Styrene monomer, inhibited/
Odor Threshold
For more Odor Threshold (Complete) data for Styrene (7 total), please visit the HSDB record page.
Refractive Index
Index of refraction: 1.5440 at 25 °C
Kovats Retention Index
1263
Other Experimental Properties
Enthalpy, 24.83 kcal/mol (liquid), 35.22 kcal/mol (gas); Gibbs (free) energy of formation, 48.37 kcal/mol (liquid), 51.10 kcal/mol (gas); entropy, 56.78 cal/deg/mol (liquid), 82.48 cal/deg/mol (gas); heat capacity, 43.64 cal/deg/mol (liquid), 29.18 cal/deg/mol (gas)
Safety & Handling
Full SDS available on request

A grade-specific Safety Data Sheet (SDS) — with the complete hazard classification, handling precautions, and transport information — is supplied with every shipment and available on request. Confirm all safety and regulatory details against the SDS for your specific grade.

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DOT / UN Transport Classification
DOT hazard class 3 placard
UN / DOT NumberUN 2055
Hazard Class / DivisionClass 3
Packing GroupIII
Proper Shipping NameStyrene monomer, stabilized

Transport classification per the UN Model Regulations / 49 CFR 172.101 Hazardous Materials Table. Confirm against the grade-specific SDS (Section 14) before shipping.

HS / Tariff Classification
Harmonized System (HS) Code — 6-digit international heading
2902 . 50
Chapter 29
Organic chemicals
Heading 29.02
Internationally harmonized (WCO HS)
Subheading 2902.50
6-digit international code — national tariff line adds further digits
Chemical Identity
CAS Number
100-42-5
Molecular Formula
C8H8
Molecular Weight
104.15 g/mol
IUPAC Name
styrene
INCI Name
STYRENE
PubChem CID
7501
InChI Key
PPBRXRYQALVLMV-UHFFFAOYSA-N
Synonyms & Trade Names
STYRENE Ethenylbenzene Phenylethylene Vinylbenzene Styrol Benzene, ethenyl- Cinnamene Styrene monomer Phenylethene Styrolene Phenethylene Vinylbenzol Styrole Vinyl benzene Styropol SO Cinnamol Styren Benzene, vinyl- Cinnamenol Ethylene, phenyl-
Full Description

Styrene (CAS 100-42-5), the aromatic vinyl monomer for polystyrene and styrenic resins. It is polymerized to polystyrene, copolymerized into SBR rubber, ABS, and SAN resins, and used as the crosslinking monomer in unsaturated polyester composites. It also serves as an intermediate for ion-exchange resins.

Frequently Asked Questions

What is styrene used for?

Styrene (CAS 100-42-5) is the aromatic vinyl monomer for polystyrene and styrenic resins. It is polymerized to polystyrene, copolymerized into SBR rubber, ABS, and SAN resins, used as the crosslinking monomer in unsaturated polyester (FRP) composites, and serves as an intermediate for ion-exchange resins.

Is styrene the same as acrylic?

No. Styrene is an aromatic vinyl monomer (C8H8) that polymerizes to polystyrene and styrenic copolymers, whereas acrylics are esters of acrylic or methacrylic acid that polymerize to acrylate polymers. They are different monomer chemistries, though both appear together in styrene-acrylic copolymers.

What is styrene made from?

Industrial styrene is produced predominantly by the catalytic dehydrogenation of ethylbenzene, which is itself made by alkylating benzene with ethylene. The monomer is supplied stabilized (inhibited) to prevent premature polymerization during storage and transport.

How is bulk styrene monomer shipped and classified for transport?

Styrene monomer is supplied stabilized and ships as UN 2055, STYRENE MONOMER, STABILIZED. We supply it to manufacturers in bulk packaging such as drums, totes, and bulk loads. Confirm packing group and current placarding requirements with your carrier and the SDS before shipment.

What HS code applies to styrene?

Styrene is classified under HS 2902.50 (styrene). CAS is 100-42-5. Verify the destination-country tariff line with your customs broker before import.

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Disclaimer. Information on this page — including properties, identifiers, hazard, transport (DOT/UN) and tariff (HS) classifications, and applications — is provided for general reference and is compiled from authoritative public sources (e.g. PubChem/ECHA, 49 CFR 172.101, the Harmonized Tariff Schedule). Values are typical and are not a guaranteed specification; the Certificate of Analysis (CoA) for the lot purchased governs. Products are sold for industrial and professional use only. Nothing here is a medical, health, or efficacy claim or advice. Always consult the current Safety Data Sheet (SDS) before handling, storage, transport or disposal, and confirm regulatory status, classification and suitability for your application and jurisdiction. Hazard, transport and tariff classifications must be verified for your specific shipment. RawSource makes no warranty, express or implied, and assumes no liability for use of this information. Trademarks. Third-party trademarks and brand names are the property of their respective owners; any reference is nominative — used only to identify a comparable product — and does not imply affiliation with, sponsorship by, or endorsement by the trademark owner.

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