Where does old, bashed up, raced and rallied carbon fiber go to die? A good question I thought, and I didn’t honestly know the answer so I toddled off to find out. I am going to be straight and say that, although I had heard noises about the low recyclability of CF, I was shocked when I really had a look under that rock!
What do you think? Never really given it a thought, given the gazillions of plastic bags, McDonald’s wrappers and now billions of rancid facemasks that litter everywhere? Let’s take a look at how sustainable this motorsport staple really is…
How Much Carbon Fiber Gets Recycled?
According to ‘The Manufacturer’, just 20% of carbon fiber gets recycled and some 35% ends up in landfill. Where does the rest go, cos that doesn’t add up to 100%? Ed. Then they then pipe on about recycling carbon fiber only uses 20% of the energy it took to make it in the first place. Something did not add up! Correct, told you, 20% and 35% doesn’t make 100%, Ed. Shut up, it was figure of speech, as in “something is not right”.
Anyway, whatever, these numbers are important when it comes to, for example, vehicle production, as it is EU mandated that 95% of a new vehicle build, by weight, must be recycled when it goes to that great motorway in the sky. If vehicles are going to be made of lighter materials for efficiency then recycling CF is a must, not a nice to have.
The carbon fiber conundrum isn’t new. The aircraft industry has been making the switch from aluminium planes to partial carbon fibre ones. In a recent BBC article it was suggested that for every 1kg of weight removed there is a saving of $1m on running costs throughout the life of an airliner. That is a mighty incentive to have strong, light planes and although it will be a while before CF planes come round for recycling (estimated at between 6000 and 8000 aircraft by 2030), we need to have a proper solution by then because there is bit of a difference between an F1 tub and a 787 Dreamliner!
Another section of industry that has quietly (or not) got on with its job but uses a LOT of CF, is the manufacture of wind turbine blades. It is estimated that there will be the thick end of 500,000 tonnes of CF type waste from this area alone by 2050
The question then is “Why is there so little CF recycling done?”.
It seems that recycling CF is not as easy as making CF and it is becoming clearer that the recycled output (rCF) is not as good quality as virgin material. Unlike recycled aluminium that goes from product to ingot to product with barely a change, that lovely woven look of virgin CF (vCF) turns into a fluffy mop when released from its resin by one of the favoured methods.
The properties change; those properties that make CF incredibly useful, the tensile strength, for example, drops by between 10 and 20% from vCF to rCF. This is due to the fact that those lovely fibres have been chopped up and are much shorter.
If science cannot deal with this it means that the rCF is a product looking for a solution as it will not be used where vCF is the complete package; one reason that CF recycling has not been quickly embraced.
There are two industrial ways of recycling – thermal and mechanical. Any other methods are currently batch only.
Mechanical involves cutting, crushing and powdering without removing resin or CF. Once the waste becomes a powder, it is reused in the manufacture of composite parts. Plainly the strength offered by fibre length will not be there but remarkably, it seems the loss in tensile strength is not as large as would be imagined.
Thermal methods are pyrolysis and solvolysis.
Pyrolysis, the use of high heat to burn off the fibre surrounding resin and Solvolysis, where solvents dissolve the resin, are currently the most used recycling methods.
Only very recently have these processes become industrially continuous rather of a batch style, which in turn changes the economics of the CF recycling.
It is the last part of the previous sentence that is important – “the economics of CF recycling”. Until relatively recently the economics didn’t add up and the legislative pressure to make them add up was not there. But the weight of sustainability weighs heavily on the aerospace and motorsport industries. Two of the biggest slaves to the lightweight composite are also two of the sectors with the worst environmental ratings.
Sustainability is now high on the agenda of all large corporates and large amounts of money are now being invested by industries which have inherently ignored environmental management. Governing bodies are now coming down heavily on those not taking sustainability seriously and motorsport is no exception.
In 2020, the FIA released their 10 year environmental plan which included reducing waste. This directive affects affects anyone involved in motorsport at any level. And whilst carbon fiber recycling represents only a tiny proportion of motorsport’s sustainability issues, the industry has invested heavily in making it an economically viable process.
So, next time you’re thinking of tacking that bit of carbon fiber onto your track car, consider where it came from and what you’ll do with it later. Reuse – Recycle!