The new method involves soaking the composites in an alcohol solvent, which slowly dissolves the epoxy that binds and gives shape to the carbon fibres. Once dissolved, the carbon fibres and the epoxy can be separated and used in new applications.
Carbon fibre is used widely in applications from aerospace to automobiles. But one of its drawbacks has been that, unlike aluminium, steel and plastics, the product is generally not easily recyclable.
The polymer matrix is usually crosslinked, just like the rubber, and it can’t be simply melted; it’s very hard to strip away the polymer to reclaim the embedded carbon fibres, which are more valuable to recycle. The research team focused on carbon fibre that uses a special type of epoxy called vitrimer epoxy to give the composite component its shape.
Vitrimers contain dynamic bonds that can alternate their structure without losing network integrity under certain conditions, the researchers let alcohol, which has small molecules, to participate in the network of alternating reactions, which effectively dissolved the vitrimer.
Jerry Qi, a professor in the Woodruff School and who leads a team of researchers affiliated with Georgia Tech’s Renewable Bioproducts Institute said the new simple recycling process has the potential to put a dent in the thousands of tons of carbon fibre waste that is generated each year in the United States and Europe.