Mar 15, 2022

Carbon fiber: the challenges of its life cycle

Carbon fiber life cycle, from manufacturing to recycling

 

Manufacturers have shown a growing interest in carbon fiber for several years, with unique physical and mechanical properties. Every second, no less than 2 kg of carbon fiber is produced globally [1]. However, if the manufacturing process is relatively mature, the management of the end of life of this material represents a major ecological issue to address.

 

The manufacture of carbon fiber

Different precursors such as polyacrylonitrile (PAN) are the basis of carbon fiber production. The process consists of oxidizing precursor fibers before moving on to the so-called “carbonization” stage to remove most non-carbon atoms. Each fiber is extremely fine, measuring between 5 and 10 micrometers in diameter, making it 2 to 20 times finer than a hair.

This manufacturing process results in carbon fibers with excellent characteristics. In addition to conducting electricity and heat, being non-flammable or permeable to X-rays, they are above all:

Lightweight: carbon fibers are nearly 70% lighter than steel [2], mainly because the carbon atoms have a low atomic mass.

Resistant: carbon fibers have excellent mechanical properties. They exhibit great resistance to traction and compression, so they are as strong as steel and sometimes even stronger!

 

The use of carbon fiber composite

Thanks to the properties of carbon fibers, the carbon fiber composite, also called carbon fiber reinforced polymer (CFRP), is ideal for industrial applications. It consists of carbon fibers spun and/or woven into sheets and mixed with polymeric resins.

Those carbon fiber composites are of increasing interest to design and manufacturing engineers, especially in aerospace, automotive, energy, marine, and other industries. They can manufacture lightweight and durable structures displaying high performance with such a material.

Moreover, this material is also essential to the ecological transition. Indeed, it represents a sustainable way to reduce CO2 emissions from aircraft, hydrogen cars, electric mobility, wind turbines, etc. For example, the carbon fiber lightens by 20% the fuselage structure of an airplane; there is 1,400 tons of CO2 for 1 ton of carbon fiber over a 10-year life cycle [3].

The demand for carbon fiber and carbon fiber composite will increase over the next few years. However, there are still two obstacles to adopting this material: its high cost and the lack of a recycling channel.

carbon fiber composite

carbon fiber composite

The end of life of carbon fiber composite

Because there is still no real processing channel for carbon fiber composite waste, most of it is destined for destruction. Indeed, production offcuts and end-of-life carbon-reinforced composite (CRC) industrial parts are generally landfilled or incinerated, even though they are not biodegradable. For example, 2,500 tons of carbon fiber waste are expected to be landfilled in the French soil by 2025 if it is not sorted and recycled [4]. Moreover, the first composite products, such as airplanes or wind turbines, are reaching the end of their life cycle after decades of use. The treatment of this waste will quickly represent a considerable amount.

Despite the development of some recycling methods, they do not satisfactorily address the scale of the problem. Indeed, traditional recycling by pyrolysis, solvolysis, or fluidized bed process, is not yet virtuous and profitable enough. It emits up to 1.2 kg of CO2 per kg recycled, and the selling price of recycled carbon fiber remains uncompetitive.

With this in mind, Fairmat has set itself a goal: to pave the way for the virtuous recycling of carbon fiber composite. The deeptech companies want to revolutionize the sector thanks to their proprietary technology. They want to create recycled and semi-finished products with low carbon footprints and maintain high-performance mechanical properties.

A new era is opening up for manufacturers to recycle their carbon-reinforced composite parts, reaching the end of their lives. And also to adopt new recycled and ecological materials with a low carbon footprint.

 

[1] Searching for Scheibe, M.; Urbaniak, M.; Goracy, K.; Bledzki, A.K. Problems connected with utilization of polymer composite products and 
waste materials—Part II. “Scrapping” of composite recreational vessels in the world in the perspective of 2030. Polimery 2019, 64, 788–794
[2] Futura Sciences, Fibre de carbone : qu’est-ce que c’est ?
[3] Toray, Life Cycle Assessment
[4] Rapport sur le marché mondial des matériaux composites réalisé par l’organisation allemande AVK