Polystyrene (PS) is a clear, crystalline resin which burns with a sooty flame. It is soluble in cyclohexane (CX), ethylbenzene (EB), ethyl acetate (etac), carbon disulphide, but insoluble in ether, acetone, phenol and saturated hydrocarbons.
Two main types of PS are produced: crystal or general purpose polystyrene (GPPS) which is a clear, amorphous resin with good stiffness and electrical properties but it is brittle; and medium and high impact polystyrene (HIPS) which contain varying levels of polybutadiene to improve toughness and impact resistance.
Polystyrene is used in a variety of consumer and commercial products with major applications in domestic appliances, construction, electronics, toys and food packaging. Included in food packaging are food and dairy containers, closures, lids, produce baskets, vending cups and fast food containers.