Carbon fibres in composite materials

One of the most used fibres in composite materials are carbon fibres. These fibres have excellent properties like light weight, high stiffness, high mechanical strength, high dimensional stability, high corrosion resistance… These properties, in combination with the high price of carbon fibres, makes it interesting to recycle these fibres.


Within the Helacs project research is performed on the recycling of composites used in aircrafts, to recover and recycle carbon fibres and process them into new composites. The recycled carbon fibres will be used as reinforcement in PA6 composites as short fibres or as nonwovens.

Before the short carbon fibres can be used, a sizing is applied on these materials by dipping the fibres in a sizing bath. By improving the sizing formulation, the adhesion between the carbon fibres and the PA6 matrix can be improved resulting in better mechanical properties of the final product. The sizing also improves the processability of the carbon fibres, making it possible to dose them during compounding with the PA6 matrix. Afterwards, short fibre reinforced composites are produced through injection moulding.

Just as with the short fibres, a sizing is applied on the nonwovens via spray application. Via compression moulding, recycled carbon fibre reinforced PA6 composites are made.

These composites are then mechanically characterized via tensile tests, impact tests, ILSS and DMA and compared to short fibre reinforced PA composites made with commercially available carbon fibres or with nonwoven reinforced PA composites without sizing. These results show that the composites made with the sized recycled carbon fibres have similar mechanical properties as the composites made with commercially available carbon fibres and the composites with the sized nonwovens even show an increase in properties of 20% or more.

By Centexbel


Latest News HELACS

  • For aircrafts that are no longer in service, the owner considers the trade-off between direct resale and disassemble & recycled. Besides that, HELACS project (Holistic processes for the cost-effective and sustainable management of End of Life of Aircraft Composite Structures) is focused on the study of the second one of these options.

  • AITIIP Technology Centre leads HELACS, a European project which aims to develop a dual methodology of controlled comprehensive dismantling in order to make possible the classification, recycling and reuse of aircraft parts made of thermoset and thermoplastic composites that have reached their end of life. Annually, the aeronautical industry is depositing more than 40,000 tons of end-of-life composite material waste in landfills. Thanks to the recovery of materials, the technology proposed by HELACS will benefit the change towards an energy efficiency model.

  • You can now download the official HELACS project brochure. A project comes to transform the dismantling process of the aircraft of the future. HELACS employs novel robotics to recycle composite materials of large components. The HELACS process is based on the application of high water pressure that will selectively chop the thermoset parts into a dimension suitable for recycling. In addition, the pyrolysis process is used for the carbonization of the thermoset matrix to reuse the carbon fibers that overcome this chemical decomposition.

This project has received funding from the Clean Sky 2 Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement Nº 101007871
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