New lease of life for carbon fiber reinforced plastics(1)

Lightweight but exceptionally strong carbon fiber reinforced plastics no longer have to be incinerated or sent to landfill once their useful life has come to an end. Pioneers of carbon fiber recycling believe that the time is coming for recycled carbon fiber reinforced plastics to take off.

Carbon fiber reinforced plastics (CFRPs) bring mechanical robustness with reduced weight to aerospace and automotive components, wind turbine blades, and sporting goods like bikes and tennis rackets. Wind turbine manufacturer Vestas is using CFRPs for wind turbine blades, where reduced weight allows for larger blades ideal for offshore sites and that are more efficient in lighter wind conditions. BMW’s i3 electric car is also employing CFRP components in the passenger compartment and McLaren has plans for a carbon fiber sports car. In the aerospace sector, Boeing’s Dreamliner aircraft relies on CFRP components to reduce weight. Lighter components means greater efficiency and lower fuel consumption during the lifetime of systems, which adds up to lower carbon emissions.

The demand for CFRPs is growing apace, with the automotive sector, for example, predicted to almost triple its usage from $ 2.4 billion in 2015 to $ 6.3 billion in 2021 [1]. These needs are currently met by virgin CF (vCF), estimated to have grown from around 16 000 tonnes a year to 140 000 tonnes by 2020 [2]. But the high financial and environmental cost of vCF is still limiting greater mass-market adoption.

But the advantages of vCF currently come at a price. The manufacture of vCF has a large environmental impact; the process is wasteful, energy intensive, and mostly reliant on fossil-fuel-derived precursor materials. Moreover, as more CFRP products find a mass market, there will be a significantly growing need for an alternative to landfill or incineration as components reach the end of their useful life. In the UK, for example, these conventional disposal routes currently account for around 98% of composite waste.  

Energy-saving in use, wasteful in manufacture

CFs can be manufactured in various ways, but the process is energy intensive, requiring very high temperatures, high cost, and usually calls for fossil-fuel-derived precursor material. Once CFs are utilized in RPs, the picture does not improve, with up to 40% of CFRP ending up as wasted during processing.

There is also an emerging waste problem on the horizon. Some 6000-8000 aircraft are due to come to the end their lives by 2030, with manufacturers like Boeing aiming to recycle at least 90% of the constituent materials – including any CFRP.

The automotive industry is also facing more stringent recycling targets. Since 2015, EU regulations have required recycling of at least 85% of end-of-life materials [3]. With the relatively short service life (10-15 years) of cars, there will be increasing amounts of CFRP to recycle.