Innovation. When it comes to high-tech textiles, most people think of intelligent clothing with woven-in sensors or batteries. Technical textiles are in the process of revolutionizing a wide variety of industries. They open up completely new market opportunities for entrepreneurs.
Textile in concrete construction sounds unusual. But if carbon, glass fibre or plastic fabric is used for reinforcement instead of rust prone reinforcement steel, this not only increases the service life of concrete structures - 200 years, experts estimate - but also saves raw materials.
"The textile concrete enables much slimmer constructions that are stable and statically safe despite their lower weight," explains Johannes Diebel. For reinforced concrete, the reinforcement steel had to be covered with 60 millimetres of concrete to protect it from corrosion. Ten millimeters are sufficient for textile reinforcement, since corrosion protection is not necessary at all. "This makes it possible to reduce the amount of cement required by 70 percent and to reduce the total weight by up to 80 percent. This saves cement, sand and energy. And less greenhouse gases will be released."
Johannes Diebel is head of research at the Forschungskuratorium Textil e. V. (Textile Research Board). (FKT) in Berlin. Technical textiles are his specialty. "Today, these products are an important second mainstay for many textile manufacturers. They are used for their functional properties and not for their aesthetic character. And they are revolutionizing our world in a way that few of us would expect."
One of Diebel's favourite examples is environmental protection through carbon fibres. Municipal wastewater, the expert explains, is rich in organic substances. Using so-called microbial fuel cells (MFCs), electricity can be generated from these microorganisms. "A positive side effect is the degradation of these substances and thus the purification of waste water. Both reduce operating costs considerably - after all, sewage treatment plants currently account for almost one third of municipal electricity costs."
The microbial fuel cells used consist of two electrodes and so-called exo-electrogenic bacteria - microorganisms in wastewater that can transfer electrons to metals in their environment. The anode of the fuel cells consists of porous material in which these microorganisms are located. The electrons transferred to the anode flow to the cathode via a wire. This produces technically usable electricity.
The performance of such fuel cells stands or falls with the electrodes - the higher the conductivity and the more bacteria can be settled, the better their performance. At RWTH Aachen University, the Institute of Textile Technology and the Institute of Applied Microbiology are therefore researching electrodes made of woven carbon fibres. Fibre fabrics offer a large surface area. Carbon is electrically conductive, resistant to chemicals and waste water and can easily be processed into textile structures in familiar processes. Better carbon electrodes increase the efficiency of microbial fuel cells.
Municipal sewage treatment plants could thus make wastewater treatment more economical and reduce costs. For medium-sized companies in the field of fabric production, this offers a very attractive opportunity to significantly increase their turnover and open up a completely new range of applications. Preliminary estimates indicate a need for at least 2.5 million square meters of carbon fabric in Germany alone.
The Textile Research Board of Trustees presents such ideas in its annual reports and also maintains a database in which topics, technologies and project partners can be searched. All the research results of recent years are available there. "This is a treasure trove especially for medium-sized companies that want to recognize trends and open up market gaps," says Diebel. "We believe that the future of the textile industry lies in sectors such as medicine and health, architecture and construction, mobility and environmental protection. Actually, there is no area of life that will not be covered by innovative textile products."
In fact, the ideas are impressive. The latest annual research report alone lists dozens of projects with revolutionary applications.
In cooperation with the Spanish company NEOS, for example, ITV Denkendorf Produktservice GmbH developed a textile-based method for the treatment of herniated discs. In this painful disease, the outer ring of the intervertebral disc tears as a result of incorrect or excessive loading of the spine. The gelatinous core swells out, presses on the nerves of the passing spinal cord and leads to an inflammatory reaction. That causes a lot of pain. In addition, the damping effect collapses at the affected site.
The current therapy consists mostly of treating the pain alone. As the disease progresses, the gelatinous core is broken down by the body and the two vertebrae above and below the affected area grow together - and this naturally impairs mobility at some point.
NEOS Surgery in Barcelona now had the idea to develop a textile screen, which is guided between the two affected vertebrae. It can be opened to close the core of the intervertebral disc and thus the crack from the inside. Initial clinical studies are currently underway in patients.
The wound dressings developed in Dresden under the auspices of the Institute for Textile Machinery and High-Performance Textile Materials Technology are also fascinating. Using textile-based sensors, they enable the continuous monitoring of poorly healing wounds, such as those of diabetics. This enables physicians to recognize disturbances in the wound healing process and react accordingly quickly. The sensors measure temperature as well as lactate and hydrogen peroxide values, are kind to the skin and withstand tension and pressure.
A project of the German Institute for Textile and Fiber Research Denkendorf (DITF) and the Institute for Textile Chemistry and Chemical Fibers (ITCF) also deals with mechanical loads. The researchers there have developed a method for measuring stress factors in composite materials and technical textiles over large areas and detecting damage in good time.
This is done using electrically conductive silver-based pastes and inks. They can be applied to the materials by screen or inkjet printing and act as electrodes. If the printed fabrics are even slightly deformed, the resistance changes. The strength and number of deformations correlates with the strength and number of negative deflections of the measurement signals. Depending on the type of stress, a typical and periodically recurring curve of the signal is created.
The process is highly efficient because only those areas need to be printed that are exposed to particular stress. This makes it possible for the first time to continuously check components over a large area - while at the same time improving the quality of the products. Manufacturers of fibre-based materials for reinforcing concrete used in construction or mechanical engineering can thus tap into a completely new source of revenue. Other profiteers are printers and finishers. Even in the field of technical textiles, where safety is of the essence, a wide variety of applications are conceivable: Belts, ropes, work, safety or military clothing, but also sports and leisure products.
"As the umbrella organisation of the 16 German textile institutes, our task is to contribute to the coordination of institutional research in the textile and clothing industry," explains Johannes Diebel. Today, more than 1200 researchers are working on new fibre-based materials, material and textile composites in these institutes. "We ensure the strategic further development of research into fiber-based materials and support the transfer of the results to small and medium-sized enterprises. Take a look at our treasure trove. I'm sure you'll find something to give your business a boost." ®
Author: Dr. Ludger Weß
Photos: DZP // Ansgar Pudenz // DITF // Carbon Concrete Composite/Thilo Schoch