Plastic: the future's orange peel
A revolutionary way to make plastic from orange peel and greenhouse gas carbon dioxide has been discovered by science researchers in the United States.
This would also offer one small solution to the growing global problem of how to control and reduce increasing levels of carbon dioxide in the earth's atmosphere.
Plastics are polymers, and are made up of a long chain of carbon-based molecules, usually made from petroleum. Limonene is a carbon-based compound that makes up around 95% of the oil found in orange peel, often used to give household cleaners a citrus smell.
Led by Professor Geoffrey Coates, the research team from Cornell, Ithaca, discovered that a derivative of this substance, limonene oxide, could be made to react with CO2 using a "helper molecule", or catalyst, producing an environmentally friendly polymer, polylimonene carbonate.
The resulting polymer has many of the same characteristics as polystyrene, a petroleum-based polymer that is used to make many disposable plastic products.
"Almost every plastic out there, from the polyester in clothing to the plastics used for food packaging and electronics, goes back to the use of petroleum as a building block," Professor Coates commented.
"If you can get away from using oil and instead use readily abundant, renewable and cheap resources then that's something we need to investigate. What's exciting about this work is that from completely renewable resources, we were able to make a plastic with very nice qualities."
He added that his research team was particularly interested in using CO2 as an alternative building block for polymers, which could be isolated for making plastics such as polylimonene carbonate instead of being pumped into the atmosphere and causing air pollution.
Professor Coates said it was vital for us to start focussing on making more recyclable, biodegradable products out of cheap, readily available and environmentally friendly materials, such as orange peel.
"Today we use things once and throw them away because plastics are so cheap and abundant," he concluded, "but it won't be like that in the future."
By Jane Kettle