#Research & Development

2023-11-02

Lignin coating makes geotextiles made from environmentally friendly natural fibers durable

Textiles are a given in civil engineering: they stabilize water protection dams, prevent runoff containing pollutants from landfills, facilitate the revegetation of slopes at risk of erosion, and even make asphalt layers of roads thinner. Until now, textiles made of highly resistant synthetic fibers have been used for this purpose, which have a very long lifetime. For some applications, however, it would not only be sufficient but even desirable for the auxiliary textile to degrade in the soil when it has done its job. Environmentally friendly natural fibers, on the other hand, often decompose too quickly. The German Institutes of Textile and Fiber Research Denkendorf (DITF) are developing a bio-based protective coating that extends their service life.

Depending on humidity and temperature, natural fiber materials can degrade in the soil in a matter of months or even a few days. In order to significantly extend the degradation time and make them suitable for geotextiles, the Denkendorf team researches a protective coating. This coating, based on lignin, is itself biodegradable and does not generate microplastics in the soil. Lignin is indeed biodegradable, but this degradation takes a very long time in nature.

Coating process of a cellulose-based nonwoven with the lignin compound using thermoplastic processing methods on a continuous coating line. Photo: DITF

Together with cellulose, Lignin forms the building materials for wood and is the "glue" in wood that holds this composite material together. In paper production, usually only the cellulose is used, so lignin is produced in large quantities as a waste material. So-called kraft lignin remains as a fusible material. Textile production can deal well with thermoplastic materials. All in all, this is a good prerequisite for taking a closer look at lignin as a protective coating for geotextiles.

Nonwoven fabric based on cellulose, coated with the lignin compound as a protective layer against degradation in the soil. Photo: DITF

Lignin is brittle by nature. Therefore, it is necessary to blend the kraft lignin with softer biomaterials. These new biopolymer compounds of brittle kraft lignin and softer biopolymers were applied to yarns and textile surfaces in the research project via adapted coating systems. For this purpose, for example, cotton yarns were coated with lignin at different application rates and evaluated. Biodegradation testing was carried out using soil burial tests both in a climatic chamber with temperature and humidity defined precisely according to the standard and outdoors under real environmental conditions. With positive results: the service life of textiles made of natural fibers can be extended by many factors with a lignin coating: The thicker the protective coating, the longer the protection lasts. In the outdoor tests, the lignin coating was still completely intact even after about 160 days of burial.

Textile materials coated with lignin enable sustainable applications. For example, they have an adjustable and sufficiently long service life for certain geotextile applications. In addition, they are still biodegradable and can replace previously used synthetic materials in some applications, such as revegetation of trench and stream banks.

Cotton yarns: with lignin coating as a protective layer against degradation in soil and reference material without coating. Photo: DITF

Thus, lignin-coated textiles have the potential to significantly reduce the carbon footprint: They reduce dependence on petroleum-based products and avoid the formation of microplastics in the soil.

Cross-section of a cotton yarn coated with lignin by extrusion process. Photo: DITF

Further research is needed to establish lignin, which was previously a waste material, as a new valuable material in industrial manufacturing processes in the textile industry.

More safety and comfort for protective clothing thanks to auxetic fabrics

When everyday materials are pulled, they stretch or elongate in the direction of the pull and become narrower in cross-section. We can also observe this property in two-dimensional textiles. Auxetic structures behave differently here. They have the striking property of not changing under tensile stress or even increasing their width or thickness. These properties are advantageous, for example, in protective textiles or textile filter media. The DITF are researching auxetic fabrics for various applications.

Panty liners prevent bacterial vaginosis

Worldwide, almost one third of women of childbearing age suffer from bacterial vaginosis. This is when the sensitive microbiome of the vagina becomes unbalanced. Such a disorder of the vaginal flora can cause urogenital infections, abscesses on the ovaries or fallopian tubes or premature births. This significantly increases the risk of infertility in women and of contracting a sexually transmitted disease or HIV.

DITF send a signal for climate protection

The German Institutes of Textile and Fiber Research Denkendorf (DITF) have successfully implemented extensive investments in photovoltaic systems at their site in Denkendorf. The systems installed on the roofs of the buildings and covered parking lots have a total installed capacity of 840 kilowatt peak (kWp). The DITF invested 1.6 million euros in this with the support of the state of Baden-Württemberg. The system was ceremonially put into operation on September 17, 2025.

4.2 million Euros for research into textile recycling

Around the world, used textiles are still rarely recycled and pile up into huge mountains of waste. A recent study by the Boston Consulting Group (BCG) drew attention to this problem. However, the low recycling rate is also due to the fact that only a small percentage of used textiles are actually suitable for recycling into high-quality materials and for demanding applications. The German Institutes of Textile and Fiber Research Denkendorf (DITF) are addressing this problem with their research.

Testing and research laboratory ensures safe and more sustainable products worldwide

For 80 years, Hohenstein has stood for independent testing, scientific expertise and practical solutions. Today, the testing and research service provider supports manufacturers and brands worldwide in making textiles, hardlines and medical devices safe, more sustainable and market-ready – thereby building trust among consumers. With an international presence and interdisciplinary expertise, Hohenstein supports its customers from production through to market launch, helping them navigate an environment of growing regulatory and societal demands.

Award-winning research for sustainable carbon fibre cycles

Sustainable recycling of carbon fibres is possible through targeted electrochemical surface modification, which makes the sizing of carbon fibres resistant to solvolysis. ITA PhD student Sabina Dann was awarded the MSW Award from RWTH Aachen University for her master's thesis on this development. The award ceremony took place on 12 November 2025 in Aachen.

Kick-off for the Textile Production of the Future: Establishment of a Textile Technology and Development Centre in Mönchengladbach, Germany

The Institut für Textiltechnik (ITA) of RWTH Aachen University, together with its partners, is pleased to announce that it has received approval for its joint initiative, ‘Textile Factory 7.0’. The goal of the project is the establishment of a technology and development centre for the textile industry in Mönchengladbach.

Perfect quality through collaboration: Machinery from Trützschler, Toyota and Murata at Zirve Tekstil

In today’s textile industry, excellence is not achieved by chance – it’s the result of deliberate decisions, technical expertise, and the courage to go beyond conventional paths. The Turkish company Zirve Tekstil has done just that: by combining the best technologies from Trützschler, Toyota and Murata, they’ve created a production setup that delivers outstanding yarn quality – recognized worldwide.

Engineering depth and diversity for composites

Airbond is the latest member of the British Textile Machinery Association (BTMA) to receive recognition for contributions to the composites industry. The engineering firm based in Pontypool, South Wales, has just received the Make UK Energy and Sustainability Award for its Lattice 3D Printing project.