Styrene (vinyl benzene, styrene monomer) 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).