Researchers Seek Plastics From Fruit

Jan. 25, 2005 — -- Think of "plastic" and "fruit" and what pops into mind is probably an eye-catching bowl of artificial produce. But one day, the ties between the two may be a lot closer than just an artistic display of phony fruit.

Researchers at Cornell University in Ithaca, N.Y., have stumbled upon a novel discovery: Citrus fruits, such as oranges and lemons, could become a key building block to environmentally friendly plastics and polymers.

"Basically, all polymers that you come into contact with today are amazing materials," said chemistry professor Geoffrey Coates, leader of the Cornell research team. But "one of the concerns is that they are all made from oil. And most producers are using oil up faster than they're finding it."

So for the past seven years, Coates and graduate students Chris Byrne and Scott Allen have been concentrating on producing plastics from more sustainable, or renewable, sources. And the fruits of their work were published in a recent edition of the Journal of American Chemical Society.

The researchers describe how limonene, a carbon-based compound produced in more than 300 plants, could be a viable ingredient in producing plastic without petroleum.

The appeal of using this naturally occurring chemical, says Coates, is that commercial industries are already tapped into it for various other uses. Many common household cleansers, for example, get their fresh citrus scent from orange peel oil, which is composed of almost 95 percent limonene.

By combining the limonene with oxygen, the resulting limonene oxide becomes a reactive compound that could take the place of traditional petroleum-based chemicals.

The other key and readily available ingredient in Cornell's natural plastic is carbon dioxide, an atmospheric gas that has been growing due in large part to an increased use of fossil fuels.