The German Institutes of Textile and Fiber Research (DITF, Denkendorf) are at the forefront of developing innovative technologies in the textile and fibre industry.
One of their significant advancements is the development of dry spinning, a process that converts preceramic fibres into oxide ceramic fibres through thermal processes. These oxide ceramic fibres are then woven to create oxide ceramic matrix composites (CMC), which find applications in various industries. DITF, the largest textile research centre in Europe, boasts over 250 scientists and technicians who cover the entire value chain from molecules and fibre chemistry to end-use products.
Founded in 1921, DITF’s primary objective is technology transfer, converting scientific knowledge into market-ready processes, products, and services.
With their focus on multifunctional, cost-efficient, and sustainable fibre technologies, DITF leverages the latest digital tools and advances in digitization across six application areas. To support these activities, DITF operates six competence centres and four technology centres.
Many of the projects and technology developments at DITF directly impact the field of fiber-reinforced composites. CW has previously reported on several innovations, including biopolymer-based composites, 3D-printed bio-based composites, self-powering composites, and textile-based sensors for composites.
DITF has also made significant advancements in thermoplastic matrices, such as polyamide 6 (PA6), with enhanced flame retardancy and improved properties and processing of lignin. Lignin is being applied as coatings for yarn and textile surfaces, providing barrier functions while enabling the production of biodegradable composites.
Furthermore, DITF has developed textile resonators that offer local variations in mass, enabling resonance frequency tuning and variable damping. Their research in this area has shown significant improvements in sound absorption at frequencies below 200 Hertz.
One of the notable patented technologies developed by DITF is HighPerCell, an environmentally friendly alternative to the traditional viscose process. HighPerCell utilizes ionic liquids, which are non-toxic and nonflammable solvents, to produce high-performance cellulose fibres from wood pulp. This technology has also been used to produce cellulose/chitin blend fibres, with up to 90% chitin sourced from shrimp shells, a waste product from the food industry.
DITF is exploring the use of HighPerCell fibres for composites and has also introduced HighPerCellCarbon, a variation that produces precursors for carbon fibre.
In the HighPerCellCarbon process, precursor cellulose filament fibres are produced using wet spinning with ionic liquids in a closed-loop system, ensuring complete solvent recycling. These cellulose filament yarns are then converted into carbon fibres using a standard, continuous, two-step oxidation and carbonization process, with DITF’s low-pressure stabilization process being an integral part of the first step. This unique approach to carbon fibre production has eliminated the generation of waste gases or toxic byproducts, making it highly sustainable. In recognition of this development, DITF was awarded the Cellulose Fibre Innovation Award in 2022.
DITF’s research extends to lignin precursors for carbon fibres as well. By utilizing dry spinning with natural and inexpensive lignin derived from wood waste, DITF has achieved significant cost and energy savings in the fibre carbonization process. The carbon yield in their process surpasses 55%, comparable to plant-based fibres.
DITF also continues to explore novel material compositions, aiming to improve properties at higher temperatures through multiphase systems and the incorporation of elements like Zirconium (Zr) and Yttrium (Y). Pilot production of Zr-toughened alumina (OxCeFi ZTA) and Zr-toughened mullite (OxCeFi ZTM) fibres is already well underway.
In conclusion, the German Institutes of Textile and Fiber Research (DITF, Denkendorf) are driving innovations in the textile and fibre industry through their research and development activities. With a focus on technology transfer and sustainable fibre technologies, DITF is making remarkable strides in various areas. Their advancements in dry spinning, composite materials, cellulose fibres, and carbon fibre production demonstrate their commitment to pushing boundaries and creating solutions for a wide range of industries.
