Lower costs thanks to future ultra-thin carbon fibres and progress in sorting used textiles using NIR (near infrared) sensors

The Institut für Textiltechnik (ITA) of RWTH Aachen University can look forward to two award winners in 2023: In his master’s thesis, ITA master’s graduate student Flávio André Marter Diniz developed polyethylene-based carbon fibres that are two to three times thinner than usual and showed how the use of PE-based precursors can reduce the price of carbon fibres by 50 percent in the future.

Lower costs thanks to future ultra-thin carbon fibres and progress in sorting used textiles using NIR (near infrared) sensors

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For his master’s thesis “Investigation of the stabilisation and carbonisation process for the production of ultra-thin polyethylene-based carbon fibres”, he was awarded the prize for the best diploma/master’s thesis in German textile mechanical engineering and prize money of 3,500 euros.

In her Bachelor’s thesis, ITA Bachelor’s graduate Annika Datko showed how used textiles can be sorted by fibre composition using near-infrared (NIR) sensor technology and, on a laboratory scale, has an average mean error of only 4 percent. Sorting according to fiber composition to subsequently carry out fibre-to-fibre recycling is the most sustainable way to produce new fibres for new products from (used) textile fibres. For her work “Experimental analysis of the sortability of used textiles containing polyester using near-infrared spectroscopy on a laboratory and industrial scale”, she received the 3,000 euros prize for the best bachelor’s thesis from the German Textile Machinery Association.

The Chairman of the Board of the Walter Reiners Foundation, Peter D. Dornier, presented the prizes at the Aachen-Dresden-Denkendort International Textile Conference in Dresden.

New manufacturing approach for more cost-effective carbon fibres

Carbon fibres are often used in growth areas such as wind turbines and pressure tanks due to their excellent properties. Unfortunately, they are very expensive due to high manufacturing costs and are not available in sufficient quantities. In his master’s thesis, Flávio André Marter Diniz developed a new and cost-effective manufacturing process by producing low-cost carbon fibres using a polyethylene precursor. Further advantages: the carbon fibres have an excellent surface quality without any noticeable structural deficits. In addition, Mr. Marter Diniz was able to reduce the time-consuming sulphonation process by 25 percent. These major advantages pave the way for a wider range of applications for carbon fibres in key industries such as wind power, automotive and aerospace.

New method for fibre-to-fibre recycling of used textiles can revolutionise textile recycling

Used textiles are currently sorted almost exclusively by hand. For fi-bre-to-fibre recycling – currently the most sustainable textile recycling option – it is important to sort textiles by fibre composition. This cannot be reliably done manually, i.e. by feel, especially with fibre blends. Annika Datko’s approach of using NIR for sorting used textiles is new. NIR sensor technology is already state of the art for recycling plastic waste, but is still in its infancy when it comes to sorting textiles.

How exactly it works: The textile sample is irradiated with NIR light. Based on the wavelengths of the reflected light and the light picked up by the detector, a material-specific spectrum is created that resembles a fingerprint. In her bachelor’s thesis, Annika Datko compared these spectra or fingerprints of textiles with different fibre components. She was able to prove that it is possible to differentiate between different fibre compositions using NIR and that it has a very low average mean error of just 4 percent on a laboratory scale.

“This method shows the way to sustainably tackle the mountains of used textiles,” says Professor Dr Thomas Gries, Director of ITA. “We are very proud that two of our students have been honoured with the prestigious Walter Reiners Prize. Every award underlines the quality of our education. Congratulations to our two winners this year!”

The VDMA Textile Machinery Association is actively involved in supporting young engineers through its Walter Reiners Foundation. Every year, the Foundation of German Textile Machinery Manufacturers awards sponsorship and sustainability prizes in the Bachelor, Diploma and Master categories. Academic work in which solutions for resource-saving products and technologies are developed is eligible for the sustainability prizes.

Featured image: Annika Datko and Peter D. Dornier/Peter D. Dornier, Flávio André Marter Diniz and Professor Dr Thomas Gries, source: ITM/TU Dresden

More information www.ita.rwth-aachen.de