| Almost every plastic out there, from the polyester in clothing to the plastics used for food packaging and electronics, uses petroleum as a building block.
A research group has made a sweet and environmentally beneficial discovery -- how to make plastics from citrus fruits such as oranges, and carbon dioxide. A paper published in the Sept. 2004 issue of the Journal of the American Chemical Society, described a way to make polymers using limonene oxide and carbon dioxide, with the help of a novel "helper molecule" -- a catalyst developed in the researchers' laboratory.
Limonene is a carbon-based compound produced in more than 300 plant species. In oranges it makes up about 95% of the oil in the peel. The other building block used was carbon dioxide (CO2), an atmospheric gas that has been rising steadily over the past century and a half -- largely due to the combustion of fossil fuels, becoming an environmentally harmful greenhouse gas. By using their catalyst to combine the limonene oxide and CO2, the Coates group produced a novel polymer, called Polylimonene Carbonate, that has many of the characteristics of polystyrene. Polystyrene is a petroleum-based plastic currently used to make many disposable plastic products. The polymer is a repeating unit, much like a strand of paper dolls. But instead of repeating dolls, the components alternate between limonene oxide and CO2, in the polymer. Neither limonene oxide nor CO2 form polymers on their own, but when put together, a promising product is created.
The Coates research team is particularly interested in using CO2 as an alternative building block for polymers. Instead of being pumped into the atmosphere as a waste product, CO2 could be isolated for use in producing plastics such as Polylimonene Carbonate.
(Based on research conducted by Cornell University) |
