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Composition of Styrofoam Cups

The trade name of polystyrene, Styrofoam is a ubiquitous part of modern western society. Commercially produced since the 1930s, the petroleum byproduct is used in packaging, take-out boxes, egg cartons, utensils and especially in disposable plates and cups. Its chemical composition includes the benzene, styrene, and ethylene molecules, as well a blowing agent, currently HCFC. Over 25 billion Styrofoam cups are used and wasted in the United States each year. A convenient insulator for hot liquids, toxic chemicals leach out of these cups into the food or liquid, especially when heated in a microwave oven.

  1. Styrene

    • Styrene monomer is a clear oily liquid extracted from petroleum. Considered a neurotoxin, styrene remains in the fatty tissues, including breast milk, of an exposed organism and may mutate chromosomes, used in cellular replication and reproduction. Exposure to styrene for extended time periods can cause imbalance, learning difficulties, fetal damage, decreased female fertility and lung cancer.

    Benzene

    • Benzene is extracted from coal and is used to convert styrene into polystyrene. A clear, colorless liquid, nearly 75 percent of all extracted benzene is used in polystyrene production. Benzene is known as a carcinogen and in high amounts is attributable to diseases such as leukemia and Hodgkin's Disease. The molecule can enter the body through the respiratory system or the skin. The Occupational Safety & Health Administration has set acceptable maximum exposure for benzene, but its composition within Styrofoam cups is negligible.

    Ethylene

    • Ethylene is a colorless gas generally used as a refrigerant and is one of the two blowing agents in Styrofoam production. Not thought to be toxic, in its gaseous phase ethylene is flammable, but not in solidified Styrofoam.

    Blowing Agents: CFCs and HCFCs

    • Until the 1970s, chloroflourocarbons (CFCs) were injected into the hard polystyrene, but as the awareness of the relationship between CFC and global warming increased, these CFCs were replaced with hydrochlorofluorocarbon (HCFC), which is essentially a CFC with a hydrogen molecule attached. Some scientists claim HCFCs deplete less ozone than CFCs, but some research indicates other environmental dangers.

    Alternatives

    • Considering the several concerns in the manufacture, use and waste of Styrofoam, nonpetroleum based alternatives can reduce pollutants and provide a chemically safer environment for the consumer. Corn plastics, bamboo and postrecycled paper are renewable, generally chemical-free and biodegradable when composted.

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