Drink glasses, polystyrene

Polystyrene, the familiar crystal-clear brittle plastic used to make disposable drinking glasses and, when foamed, the lightweight white cups for hot drinks, is usually made by free-radical polymerization. Commercially an initiator is not used because polymerization begins spontaneously at elevated temperatures. At lower temperatures a variety of initiators could be used (e.g., 2,2 -azobis-(2-methylpropionitrile) which was used in the free-... 

Styrene is a major industrial chemical, primarily because of its use in making polystyrene. Polystyrene is a clear, hard, colorless solid at room temperature that can be molded easily at 250°C. More than 6 million tons of polystyrene are produced in the United States each year to make food containers, toys, electrical parts, insulating panels, appliance and fm-niture components, and many other items. The variation in properties shown by polystyrene products is typical of synthetic polymers. For example, a clear polystyrene drinking glass that is britde and breaks into sharp pieces somewhat like glass is much different from a polystyrene coffee cup that is soft and pliable. 

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