US scientists have discovered a way to make plastics from orange peel, using the greenhouse gas carbon dioxide.
Limonene is an oil in orange peel and can be used to make polymers
Cornell University researchers created a novel polymer using CO2, an oil present in orange peel and a catalyst that speeds the reaction along.
The team hopes CO2 could one day be collected for making plastics instead of being pumped into the atmosphere.
Details of the research appear in the Journal of the American Chemical Society.
Plastics are polymers, long-chained carbon-based (organic) molecules.
Limonene is a carbon-based compound that makes up about 95% of the oil in orange peel and is used to give household cleaners their citrus smell.
Geoffrey Coates, a professor of chemistry at Cornell, in Ithaca, and colleagues used a derivative of this oil called limonene oxide as one of the building blocks for their polymer.
The researchers used a helper molecule, or catalyst, to get the limonene oxide to react with CO2 and form a new polymer called polylimonene carbonate.
This polymer has many of the characteristics of polystyrene, which is used in numerous 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," said Professor Coates.
"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."
Coates' team is interested in using carbon dioxide as an alternative building block for polymers in industry. The gas could be isolated and used to produce plastics such as polylimonene oxide.
CO2 is the principal greenhouse gas caused by human activities, and is emitted by fossil fuel burning and deforestation.