Styrene Monomer
Description
Styrene (vinyl benzene, styrene monomer SM) is a colorless to yellowish oily liquid with a distinctive aromatic odor. It is sparingly soluble in water but soluble in alcohols, ethers and carbon disulfide. This valuable monomer is flammable, reactive and toxic. Styrene Monomer is a light liquid. It has a low vapor pressure and high refractive index. It is chemically reactive and undergoes polymerization readily (by heat, light or peroxide catalysts). Polymerization results in volumetric shrinkage (17%) and exothermic heat (17.8 Kcal/mole).
Properties
| Parameter | Unit | Quantity |
|---|
| Molecular weight | g/mol | 104.14 |
| Refractive index | °C at 29°C | 1.5445 |
| Boiling point | °C | 146 |
| Freezing point | °C | -30 to -32 |
| Vapor density | air = 1 at 15°C | 3.6 |
| Viscosity | cp at 20°C | 0.76 |
| CAS number | 100-42-5 |
| IUPAC name | Styrene |
Specifications
| Parameter | Unit | Quantity | Test Method |
|---|
| Purity | wt % | 99.7 min. | ASTM D-5135 |
| Polymers | ppm, wt | 10 max. | ASTM D-2121 |
| Color | APHA | 10 max. | ASTM D-1209 |
| Aldehydes (as benzaldehyde) | wt % | 0.01 max. | ASTM D-2119 |
| Inhibitor (as TBC) | ppm, wt | 14-18 (1) | ASTM D-4590 |
| Peroxides (as H2O2) | ppm, wt | 50 max. | ASTM D-2340 |
| Total sulfur (as S) | ppm, wt | 5 max. | ASTM D-5623 |
| Total chlorides (as CI) | wt % | 0.005 max. | UOP-395/66 |
| Ethyl benzene | ppm, wt | 500 max. | ASTM D-5135 |
| Density | at 15°C | 0.909-0.911 | ASTM D-4052 |
(1) 14 - 18 PPMW, FOB KFIP, Al-Jubail
50 - 100 PPMW for all styrene truck shipments calculated as per Shipping Operations procedure.
Special TBC requirements will be evaluated on a case by case basis. TBC addition is only possible if (a) ship Master & customer accept to add the TBC on-board marine ship, and (b) only if customer accepts that TBC will not be certified after the addition on-board the marine ship.
Note:
- ASTM : American Society for Testing and Materials
Hazards and safety
Styrene Monomer liquid has a distinctive pleasant odor, but is harmful if swallowed and burns the skin and eyes. Its vapors are irritating to eyes and throat; if inhaled, it will cause dizziness and loss of consciousness. This monomer is considered to be a moderately toxic, highly flammable and a highly reactive chemical. In the event of a fire, the fire-fighting group should be at a safe distance and protected from explosions and use dry chemicals or carbon dioxide.
| Parameter | Unit | Quantity |
|---|
| Threshold limit value | ppm | 100 |
| Ignition point | °C | 490 |
| Flash point | °C | 31-32.5 |
| Flammable limits in air | vol % | 1.1-6.1 |
| UN or ID NO. | | 2055 |
Applications
Styrene Monomer is most commonly used in the production of valuable styrene homopolymers and copolymers, which are either solid (SPS) or expandable (EPS). Some SPS grades are used for the production of disposable transparent containers and EPS grades are useful in the fabrication of blocks for thermal insulation and boxes for vegetables and fruits. High Impact Polystyrene (HIPS) is polystyrene blended with rubber for better mechanical properties useful in the production of dairy products, packaging materials and sheets. The copolymers of SM with butadiene and/or acrylonitrile create valuable products combining characteristics of synthetic rubbers and strong plastics.
Storage and handling
Styrene Monomer is stored in insolated carbon steel tanks. To prevent Styrene polymerization, the Styrene temperature must be controlled at around 10-11°C. Also, a polymerization inhibitor must be added. Normally, Tertiary Butylcatechol (TBC) is used with a concentration of 10-15 PPM. In hot climates and during the transportation of Styrene, the initial TBC level should be increased to around 50 PPM to avoid autocatalytic polymerization which becomes self-sustaining above 20°C. The exact TBC level will depend on the prevailing ambient temperature and the duration of the transportation. As a general rule when transporting Styrene, you should avoid contact with copper, copper alloys, brass and PVC. Avoid contact of Styrene (containing low level of TBC) with oxygen as it creates hazardous peroxides. Avoid contact with air. Avoid static electricity, sparks or any open flame. Keep liquid temperature and vapor venting under rigged control. Avoid direct or prolonged exposure to the sunlight and ambient conditions. Indoor storage should be in a standard flameproof storage room with temperature controlled lower than 25°C. Use safety goggles, rubber gloves and chemical cartridge respirators.
Packaging
Our premium quality Styrene Monomer is shipped in chemical vessels (Type 2 of the International Maritime Organization Code). Our Styrene Monomer is also transferred via suitable road trucks arranged by us or by customers. Glass is particularly suitable for handling Styrene Monomer in small quantities, and stable plastic materials may also be used. Precautionary labeling: “Styrene Monomer inhibited, flammable liquid, harmful if swallowed”.