Recycling of thermoplastic CFRP with

electrodynamic fragmentation

Clemens DRANSFELD1

Maxime ROUX 1

, Nicolas EGUEMANN2

,Lian GIGER1,2

,

1 Institute of Polymer Engineering (IKT),

FHNW University of Applied Sciences and Arts Northwestern Switzerland, Windisch,

Switzerland.

2 Cross Composite AG, Steckborn, Switzerland.

5ème édition de la Journée technologique de la plasturgie, le 12 mai 2016 à Fribourg

Content

• Recycling of thermoplastic Carbon Composites

• Promising novel approaches

• Conclusion & Outlook

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Recycling of thermoplastic composites

Opportunities

• Possibility to reprocess the polymer

matrix

• Rate up to 100% achievable

Challenges

• Mechanical shredding of the entire

CFRP parts, but:

• Huge wear of the shredder blades with

aerospace CF/PEEK due to high fibres

contents and high fracture toughness of

matrix,

• Production of fragments with short fibres.

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PEEK/CF after

mechanical

shredding process

(source FHNW)

TPU/2x2 Twill GRP after shreddering

(Source: Rasheed et al. 2013)

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Source: Selfrag

Process parameters

• Voltage between 50 to 200 kV,

• Pulse rise time below 5µs.

Selfrag lab unit: Batch process,

limited size, suitable for small

amount.

C. Dransfeld 5ème édition de la Journée technologique de la plasturgie

Novel alternative to mechanical shredding:

Electrodynamic fragmentation (EdF) or High Voltage fragmentation (HVF)

• A material placed in water is separated through its natural boundaries using high voltage

discharges.

• Breakdown voltage versus pulse risetime: Water acts as isolating medium

Electrodynamic fragmentation (EdF) or High Voltage fragmentation (HVF)

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(Blum et. al 2000, modified)

Mechanical testing: Recycled versus original

• Mechanical behaviour similar to initial door hinges

• Maximal load:

• Only 17% reduction compared to chopped tapes

(20mm),

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Loading conditions

C. Dransfeld 5ème édition de la Journée technologique de la plasturgie

Conclusions

Cradle to cradle recycling of CF PEEK is possible

Successful grinding of a PEEK/CF composite with high content of long carbon fibres.

Production of a complex parts with:

• 100% of recycled materials which closes

the cradle to cradle loop

(Low downcycling).

Promising results:

• Only a slight reduction of the

mechanical properties. (Shorter

fragments, partial reduced polymers

content at the surface of the fragments)

• No special treatments between the

recycling and the reprocessing.

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Further reading with in depth information ….

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Acknowledgements

• Clean Sky JTI, Eco-Design ITD,

• Airbus helicopters Germany,

• Selfrag AG, Switzerland.

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Thank you for your attention. Questions?

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Point of Contact:

Clemens Dransfeld

Institut of Polymer Engineering

Klosterzelgstrasse 2

5210 Windisch

Switzerland

clemens.dransfeld@fhnw.ch

www.fhnw.ch/technik/ikt/

C. Dransfeld 5ème édition de la Journée technologique de la plasturgie