Automotive

Simple recycling process aims to cut down on carbon fiber waste

Simple recycling process aims ...
A team at Georgia Tech wants to recycle carbon fiber using a simple, scalable process
A team at Georgia Tech wants to recycle carbon fiber using a simple, scalable process
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The strands in the carbon fiber are the valuable bits that researchers want to get their hands on
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The strands in the carbon fiber are the valuable bits that researchers want to get their hands on
A team at Georgia Tech wants to recycle carbon fiber using a simple, scalable process
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A team at Georgia Tech wants to recycle carbon fiber using a simple, scalable process
Carbon fiber is finding its way into more automotive applications, from tubs to wheels
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Carbon fiber is finding its way into more automotive applications, from tubs to wheels
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With its combination of lightness and strength, carbon fiber is being used in a growing range of aerospace and automotive applications. Unfortunately, the weave isn't easily recyclable, unlike more traditional steel or aluminum. A team at Georgia Tech is trying to change that, using a new method to recycle the materials in thermoset carbon fiber.

In spite of all its benefits, carbon fiber is a tricky material to deal with when it's reached the end of its life. Steel and aluminum can be recycled, but the valuable carbon strands locked away in pieces of thermoformed carbon fiber are difficult to get to.

Because the polymer matrix used to hold the carbon fibers is usually crosslinked, it can't simply be melted down or stripped away. That means a lot of carbon fiber pieces are thrown away, which is both an expensive waste and bad for the environment.

The Georgia Tech team focused on a specific type of carbon fiber which gets its shape from vitrimer epoxy. A piece of the material is soaked in alcohol, which slowly dissolves the epoxy binding the carbon strands together. Once the process is complete, the fibers and epoxy can simply be separated and used in new applications.

"Vitrimers contain dynamic bonds that can alternate their structure without losing network integrity under certain conditions," says Kai Yu, postdoctoral researcher in the George W. Woodruff School of Mechanical Engineering at Georgia Tech. "We let alcohol, which has small molecules, to participate in the network of alternating reactions, which effectively dissolved the vitrimer."

Yu also says the simple process is easily scaled up, saying "it's very easy to operate, so there's no limit to the size."

The team says that should the process be adopted, it has the potential to drastically cut the amount of carbon fiber waste produced each year. It certainly looks simpler than the system being used by bike manufacturer Trek, which began a carbon fiber recycling program in 2011 and involves cutting waste material into squares and then heating them in an almost oxygen-free environment to free up the fibers.

The findings are published in the journal Advanced Functional Materials.

Source: Georgia Tech

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3 comments
RXStephen
How is that bad for the environment? Take it to the dump and put the carbon back where it came from, under ground. This sounds like a great way to take carbon out of the cycle.
Howell Haus
I agree that it's important to develop a method to recover expensive, energy intensive carbon and keep it out of landfills. I'm more curious to know how the remaini g alcohol solution is disposed of and how its contents, which are almost certainly toxic, are disposed of or reused... air, water, soil. The better they all are, the better it all is.
jerryd
Sorry but the cf is so degraded it hss less strength than fg making it not worth recycling, especially wadting ethanol to fo it. Best for all composites is heat it till the resin gasifies and turn it into fuels and use the fibers for filler. Sometimes things are not worth recycling. Fact is cf is rarely worth it as fg, kevlar, other fibers are far better in most cases like car bodies, chassis.