Textination Newsline

The low-cost FibeRobo, which is compatible with existing textile manufacturing techniques, could be used in adaptive performance wear or compression garments.

Researchers from MIT and Northeastern University developed a liquid crystal elastomer fiber that can change its shape in response to thermal stimuli. The fiber, which is fully compatible with existing textile manufacturing machinery, could be used to make morphing textiles, like a jacket that becomes more insulating to keep the wearer warm when temperatures drop.

Instead of needing a coat for each season, imagine having a jacket that would dynamically change shape so it becomes more insulating to keep you warm as the temperature drops.
A programmable, actuating fiber developed by an interdisciplinary team of MIT researchers could someday make this vision a reality. Known as FibeRobo, the fiber contracts in response to an increase in temperature, then self-reverses when the temperature decreases, without any embedded sensors or other hard components.

The low-cost fiber is fully compatible with textile manufacturing techniques, including weaving looms, embroidery, and industrial knitting machines, and can be produced continuously by the kilometer. This could enable designers to easily incorporate actuation and sensing capabilities into a wide range of fabrics for myriad applications.

The fibers can also be combined with conductive thread, which acts as a heating element when electric current runs through it. In this way, the fibers actuate using electricity, which offers a user digital control over a textile’s form. For instance, a fabric could change shape based on any piece of digital information, such as readings from a heart rate sensor.

“We use textiles for everything. We make planes with fiber-reinforced composites, we cover the International Space Station with a radiation-shielding fabric, we use them for personal expression and performance wear. So much of our environment is adaptive and responsive, but the one thing that needs to be the most adaptive and responsive — textiles — is completely inert,” says Jack Forman, a graduate student in the Tangible Media Group of the MIT Media Lab, with a secondary affiliation at the Center for Bits and Atoms, and lead author of a paper on the actuating fiber.

He is joined on the paper by 11 other researchers at MIT and Northeastern University, including his advisors, Professor Neil Gershenfeld, who leads the Center for Bits and Atoms, and Hiroshi Ishii, the Jerome B. Wiesner Professor of Media Arts and Sciences and director of the Tangible Media Group. The research will be presented at the ACM Symposium on User Interface Software and Technology.

Morphing materials
The MIT researchers wanted a fiber that could actuate silently and change its shape dramatically, while being compatible with common textile manufacturing procedures. To achieve this, they used a material known as liquid crystal elastomer (LCE).

A liquid crystal is a series of molecules that can flow like liquid, but when they’re allowed to settle, they stack into a periodic crystal arrangement. The researchers incorporate these crystal structures into an elastomer network, which is stretchy like a rubber band.

As the LCE material heats up, the crystal molecules fall out of alignment and pull the elastomer network together, causing the fiber to contract. When the heat is removed, the molecules return to their original alignment, and the material to its original length, Forman explains.

By carefully mixing chemicals to synthesize the LCE, the researchers can control the final properties of the fiber, such as its thickness or the temperature at which it actuates.

They perfected a preparation technique that creates LCE fiber which can actuate at skin-safe temperatures, making it suitable for wearable fabrics.

“There are a lot of knobs we can turn. It was a lot of work to come up with this process from scratch, but ultimately it gives us a lot of freedom for the resulting fiber,” he adds.
However, the researchers discovered that making fiber from LCE resin is a finicky process. Existing techniques often result in a fused mass that is impossible to unspool.

Researchers are also exploring other ways to make functional fibers, such as by incorporating hundreds of microscale digital chips into a polymer, utilizing an activated fluidic system, or including piezoelectric material that can convert sound vibrations into electrical signals.

Fiber fabrication
Forman built a machine using 3D-printed and laser-cut parts and basic electronics to overcome the fabrication challenges. He initially built the machine as part of the graduate-level course MAS.865 (Rapid-Prototyping of Rapid-Prototyping Machines: How to Make Something that Makes [almost] Anything).

To begin, the thick and viscous LCE resin is heated, and then slowly squeezed through a nozzle like that of a glue gun. As the resin comes out, it is cured carefully using UV lights that shine on both sides of the slowly extruding fiber.

If the light is too dim, the material will separate and drip out of the machine, but if it is too bright, clumps can form, which yields bumpy fibers.

Then the fiber is dipped in oil to give it a slippery coating and cured again, this time with UV lights turned up to full blast, creating a strong and smooth fiber. Finally, it is collected into a top spool and dipped in powder so it will slide easily into machines for textile manufacturing.
From chemical synthesis to finished spool, the process takes about a day and produces approximately a kilometer of ready-to-use fiber.

“At the end of the day, you don’t want a diva fiber. You want a fiber that, when you are working with it, falls into the ensemble of materials — one that you can work with just like any other fiber material, but then it has a lot of exciting new capabilities,” Forman says.

Creating such a fiber took a great deal of trial and error, as well as the collaboration of researchers with expertise in many disciplines, from chemistry to mechanical engineering to electronics to design.

The resulting fiber, called FibeRobo, can contract up to 40 percent without bending, actuate at skin-safe temperatures (the skin-safe version of the fiber contracts up to about 25 percent), and be produced with a low-cost setup for 20 cents per meter, which is about 60 times cheaper than commercially available shape-changing fibers.

The fiber can be incorporated into industrial sewing and knitting machines, as well as nonindustrial processes like hand looms or manual crocheting, without the need for any process modifications.
The MIT researchers used FibeRobo to demonstrate several applications, including an adaptive sports bra made by embroidery that tightens when the user begins exercising.

They also used an industrial knitting machine to create a compression jacket for Forman’s dog, whose name is Professor. The jacket would actuate and “hug” the dog based on a Bluetooth signal from Forman’s smartphone. Compression jackets are commonly used to alleviate the separation anxiety a dog can feel while its owner is away.

In the future, the researchers want to adjust the fiber’s chemical components so it can be recyclable or biodegradable. They also want to streamline the polymer synthesis process so users without wet lab expertise could make it on their own.

Forman is excited to see the FibeRobo applications other research groups identify as they build on these early results. In the long run, he hopes FibeRobo can become something a maker could buy in a craft store, just like a ball of yarn, and use to easily produce morphing fabrics.

“LCE fibers come to life when integrated into functional textiles. It is particularly fascinating to observe how the authors have explored creative textile designs using a variety of weaving and knitting patterns,” says Lining Yao, the Cooper-Siegel Associate Professor of Human Computer Interaction at Carnegie Mellon University, who was not involved with this work.

This research was supported, in part, by the William Asbjornsen Albert Memorial Fellowship, the Dr. Martin Luther King Jr. Visiting Professor Program, Toppan Printing Co., Honda Research, Chinese Scholarship Council, and Shima Seiki. The team included Ozgun Kilic Afsar, Sarah Nicita, Rosalie (Hsin-Ju) Lin, Liu Yang, Akshay Kothakonda, Zachary Gordon, and Cedric Honnet at MIT; and Megan Hofmann and Kristen Dorsey at Northeastern University.

Wind turbines typically operate for 20 to 30 years before they are undergoing dismantling and recycling. However, the recycling of fiber composites, especially from the thick-walled rotor blade parts, has been inadequate until now. The prevailing methods involve thermal or mechanical recycling. For a sustainable and holistic recycling process, a research consortium led by Fraunhofer IFAM is pooling their expertise to recover the fibers through pyrolysis. Subsequent surface treatment and quality testing of the recyclates allow for them to be used again in industry.

Today, the vast majority of wind turbines can already be recycled cleanly. In the case of rotor blades, however, recycling is only just beginning. Due to the 20-year operation period and the installation rates, the blade volume for recycling will be increasing in the coming years and decades. In 2000, for example, around 6,000 wind turbines were erected in Germany, which now need to be fed into a sustainable recycling process. In 2022, about 30,000 onshore and offshore wind turbines with a capacity of 65 gigawatts were in operation in Germany alone.

As wind energy is the most important cornerstone for a climate-neutral power supply, the German government has set itself the goal of further increasing its wind energy capacity by 2030 by installing larger and more modern turbines. Rotor blades will become longer, the proportion of carbon fibers used will continue to increase - and so will the amount of waste. In addition, the existing material mix in rotor blades is expected to increase in the future and precise knowledge of the structure of the components will become even more important for recycling. This underscores the urgency of developing sustainable processing methods, especially for recycling the thick-walled fiber composites in the rotor blades.

Economic and ecological recycling solution for fiber composites on the horizon
Rotor blades of wind turbines currently up for recycling consist of more than 85 percent of glass- and carbon-fiber-reinforced thermosets (GFRP/CFRP). A large proportion of these materials is found in the flange and root area and within the fiber-reinforced straps as thick-walled laminates with a wall thicknesses of up to 150 mm. Research into high-quality material fiber recycling as continuous fibers is of particular importance, not only because of the energy required for carbon fiber production. This is where the project "Pyrolysis of thick-walled fiber composites as a key innovation in the recycling process for wind turbine rotor blades" – "RE SORT" for short – funded by the German Federal Ministry of Economics and Climate Protection comes in. The aim of the project team is the complete recycling by means of pyrolysis.

A prerequisite for high-quality recycling of fiber composites is the separation of the fibers from the mostly thermoset matrix. Although pyrolysis is a suitable process for this purpose, it has not yet gained widespread adoption. Within the project, the project partners are therefore investigating and developing pyrolysis technologies that make the recycling of thick-walled fiber composite structures economically feasible and are technically different from the recycling processes commonly used for fiber composites today. Both quasi-continuous batch and microwave pyrolysis are being considered.

Batch pyrolysis, which is being developed within the project, is a pyrolysis process in which the thermoset matrix of thick fiber composite components is slowly decomposed into oily and especially gaseous hydrocarbon compounds by external heating. In microwave pyrolysis, energy is supplied by the absorption of microwave radiation, resulting in internal rapid heat generation. Quasi-continuous batch pyrolysis as well as microwave pyrolysis allow the separation of pyrolysis gases or oils. The planned continuous microwave pyrolysis also allows for the fibers to be preserved and reused in their full length.

How the circular economy succeeds - holistic utilization of the recycled products obtained
In the next step, the surfaces of the recovered recycled fibers are prepared by means of atmospheric plasmas and wet-chemical coatings to ensure their suitability for reuse in industrial applications. Finally, strength tests can be used to decide whether the recycled fibers will be used again in the wind energy industry or, for example, in the automotive or sporting goods sectors.

The pyrolysis oils and pyrolysis gases obtained in batch and microwave pyrolysis are evaluated with respect to their usability as raw materials for polymer synthesis (pyrolysis oils) or as energy sources for energy use in combined heat and power (CHP) plants (pyrolysis gases).

Both quasi-continuous batch pyrolysis and continuous-flow microwave pyrolysis promise economical operation and a significant reduction in the environmental footprint of wind energy. Therefore, the chances for a technical implementation and utilization of the project results are very good, so that this project can make a decisive contribution to the achievement of the sustainability and climate goals of the German Federal Government.

In two new studies, North Carolina State University researchers designed and tested a series of textile fibers that can change shape and generate force like a muscle. In the first study, the researchers focused on the materials’ influence on the artificial muscles’ strength and contraction length. The findings could help researchers tailor the fibers for different applications.

In the second, proof-of-concept study, the researchers tested their fibers as scaffolds for live cells. Their findings suggest the fibers – known as “fiber robots” – could potentially be used to develop 3D models of living, moving systems in the human body.

“We found that our fiber robot is a very suitable scaffold for the cells, and we can alter the frequency and contraction ratio to create a more suitable environment for cells,” said Muh Amdadul Hoque, graduate student in textile engineering, chemistry and science at NC State. “These were proof-of concept studies; ultimately, our goal is to see if we can study these fibers as a scaffold for stem cells, or use them to develop artificial organs in future studies.”
 
Researchers made the shape-changing fibers by encapsulating a balloon-like tube, made of a material similar to rubber, in a braided textile sheath. Inflating the interior balloon with an air pump makes the braided sheath expand, causing it to shorten.

The researchers measured the force and contraction rates of fibers made from different materials in order to understand the relationship between material and performance. They found that stronger, larger diameter yarns generated a stronger contraction force. In addition, they found that the material used to make the balloon impacted the magnitude of the contraction and generated force.
 
“We found that we could tailor the material properties to the required performance of the device,” said Xiaomeng Fang, assistant professor of textile engineering, chemistry and science at NC State. “We also found that we can make this device small enough so we can potentially use it in fabric formation and other textile applications, including in wearables and assistive devices.”
 
In a follow-up study, researchers evaluated whether they could use the shape-changing fibers as a scaffold for fibroblasts, a cell type found in connective tissues that help support other tissues or organs.

“The idea with stretching is to mimic the dynamic nature of how your body moves,” said Jessica Gluck, assistant professor of textile engineering, chemistry and science at NC State, and a study co-author.

They studied the cells’ response to the motion of the shape-changing fibers, and to different materials used in the fibers’ construction. They found the cells were able to cover and even penetrate the fiber robot’s braiding sheath. However, they saw decreases in the cells’ metabolic activity when the fiber robot’s contraction extended beyond a certain level, compared to a device made of the same material that they kept stationary.

The researchers are interested in building on the findings to see if they could use the fibers as a 3D biological model, and to investigate whether movement would impact cell differentiation. They said their model would be an advance over other existing experimental models that have been developed to show cellular response to stretching and other motion, since they can only move in two dimensions.
 
“Typically, if you want to add stretch or strain on cells, you would put them onto a plastic dish, and stretch them in one or two directions,” Gluck said. “In this study, we were able to show that in this 3D dynamic culture, the cells can survive for up to 72 hours.

“This is particularly useful for stem cells,” Gluck added. “What we could do in the future is look at what could happen at the cellular level with mechanical stress on the cells. You could look at muscle cells and see how they’re developing, or see how the mechanical action would help differentiate the cells.”

The study, “Effect of Material Properties on Fiber-Shaped Pneumatic Actuators Performance” was published in Actuators on March 18. Emily Petersen was a co-author. The study was funded by start-up funding awarded to Fang from the Department of Textile Engineering, Chemistry and Science at NC State.

The study, “Development of a Pneumatic-Driven Fiber-Shaped Robot Scaffold for Use as a Complex 3D Dynamic Culture System” was published online in Biomimetics on April 21. In addition to Gluck, Hoque and Fang, co-authors included Nasif Mahmood, Kiran M. Ali, Eelya Sefat, Yihan Huang, Emily Petersen and Shane Harrington. The study was funded by the NC State Wilson College of Textiles, the Department of Textile Engineering, Chemistry and Science and the Wilson College of Textiles Research Opportunity Seed Fund Program.

As humanity grapples with climate change and rising sea levels, our collective imagination is more critical than ever. In light of this, bcomp presents the phenomenal work initiated by the students from Institut auf dem Rosenberg in St. Gallen and SAGA Space Architects. They’ve developed an extraordinary solution to address the environmental challenges we face: the ‘Blue Nomad’ floating habitat.

‘Blue Nomad’ is a solar-powered home designed for comfortable living on the ocean. It symbolises a future where we must explore and adapt to the changing earth’s environment. Drawing inspiration from the first Polynesian nomadic settlements and equipped with solar panels for self-sustainability, the habitat promotes a vision of living and traveling on water.

bcomp is particularly excited about the project as the scaled model that was exhibited in London and Monaco prominently features their very own ampliTex™ flax fibres. A plan of building an actual prototype of the floating home is being developed by Institut auf dem Rosenberg and SAGA. It could be made from a structurally optimised weave of flax fibre, showcasing the future of organic and regenerative high-performance materials replacing conventional synthetic and fossil-based technologies. As a company, bcomp is proud to provide sustainable material solutions, and seeing their flax fibres used in such an innovative and meaningful project is both humbling and inspiring.

‘Blue Nomad’ isn’t just a solitary habitat, but a concept for a new kind of community. Imagined as modular blocks, these habitats can form larger communities and oceanic farms, allowing inhabitants to share resources while moving from one oceanic farm to the next. It’s a striking vision of a future where the lines between land and water blur, and sustainability and community building lie at the heart of human settlements.

But this vision is not just theoretical. Plans are being made for a maiden voyage of ‘Blue Nomad’ across Europe, powered purely by solar energy, promoting ocean sustainability, climatology, and future nomadism.

This project serves as a powerful reminder of what can be achieved when education, innovative design, and sustainability are united. The ‘Blue Nomad’ represents the future we envision – a future where sustainable materials play a crucial role in safeguarding our planet.

The ‘Blue Nomad’ project was exhibited at the London Design Biennale 2023 as well as the Monaco Energy Boat Challenge where it was captivating visitors and garnering significant attention from the public.    

Electronically conductive fibres are already in use in smart textiles, but in a recently published research article, ionically conductive fibres have proven to be of increasing interest. The so-called ionofibres achieve higher flexibility and durability and match the type of conduction our body uses. In the future, they may be used for such items as textile batteries, textile displays, and textile muscles.

The research project is being carried out by doctoral student Claude Huniade at the University of Borås and is a track within a larger project, Weafing, the goal of which is to develop novel, unprecedented garments for haptic stimulation comprising flexible and wearable textile actuators and sensors, including control electronics, as a new type of textile-based large area electronics.

WEAFING stands for Wearable Electroactive Fabrics Integrated in Garments. It started 1 January 2019 and ended 30 June 2023.

These wearables are based on a new kind of textile muscles which yarns are coated with electromechanically active polymers and contract when a low voltage is applied. Textile muscles offer a completely novel and very different quality of haptic sensation, accessing also receptors of our tactile sensory system that do not react on vibration, but on soft pressure or stroke.

Furthermore, being textile materials, they offer a new way of designing and fabricating wearable haptics and can be seamlessly integrated into fabrics and garments. For these novel form of textile muscles, a huge range of possible applications in haptics is foreseen: for ergonomics, movement coaching in sports, or wellness, for enhancement of virtual or augmented reality applications in gaming or for training purposes, for inclusion of visually handicapped people by providing them information about their environment, for stress reduction or social communication, adaptive furniture, automotive industry and many more.

In Claude Huniade’s project, the goal is to produce conductive yarns without conductive metals.

"My research is about producing electrically conductive textile fibres, and ultimately yarns, by coating non-metals sustainably on commercial yarns. The biggest challenge is in the balance between keeping the textile properties and adding the conductive feature," said Claude Huniade.

Currenty, the uniqueness of his research leans towards the strategies employed when coating. These strategies expand to the processes and the materials used.

Uses ionic liquid
One of the tracks he investigates is about a new kind of material as textile coating, ionic liquids in combination with commercial textile fibres. Just like salt water, they conduct electricity but without water. Ionic liquid is a more stable electrolyte than salt water as nothing evaporates.

"The processable aspect is an important requirement since textile manufacturing can be harsh on textile fibres, especially when upscaling their use. The fibres can also be manufactured into woven or knitted without damaging them mechanically while retaining their conductivity. Surprisingly, they were even smoother to process into fabrics than the commercial yarns they are made from," explained Claude Huniade.

Ionofibres could be used as sensors since ionic liquids are sensitive to their environment. For example, humidity change can be sensed by the ionofibers, but also any stretch or pressure they are subjected to.

"Ionofibres could truly shine when they are combined with other materials or devices that require electrolytes. Ionofibres enable certain phenomena currently limited to happen in liquids to be feasible in air in a lightweight fashion. The applications are multiple and unique, for example for textile batteries, textile displays or textile muscles," said Claude Huniade.

Needs further research
Yet more research is needed to combine the ionofibres with other functional fibres and to produce the unique textile devices.

How do they stand out compared to common electronically conductive fibres?

"In comparison to electronically conductive fibres, ionofibers are different in how they conduct electricity. They are less conductive, but they bring other properties that electronically conductive fibers often lack. Ionofibres achieve higher flexibility and durability and match the type of conduction that our body uses. They actually match better than electronically conductive fibres with how electricity is present in nature," he concluded.

Scientists at the Fraunhofer Institute for Biomedical Engineering IBMT have been working with international partners to develop a technology platform to help relieve the symptoms of muscle tremors. Tiny biocompatible electrodes in the muscles, combined with external electrodes and controllers, form an intelligent network of sensors and actuators to detect muscle signals and provide electrical stimuli as needed. Together with exoskeletons, the technology could also help people with spinal cord injuries.

A compact controller on a belt or under a jacket, a couple of discreet textile electrodes on the arms and legs, and electrodes three centimeters long and barely a millimeter thin in the muscle are all it will take to help people with tremor disorders in the future. Whenever muscle tremors start, the system sends electrical stimuli to the muscles; these stimuli are registered by the nervous system. The nervous system then stops sending interfering signals to the muscles, which settle down again. That is the basic idea behind the technology that scientists from Fraunhofer IBMT have been working on together with project partners by developing, manufacturing, integrating and experimentally testing a set of intramuscular and external electrodes and associated controllers.

The scientists have already made some concrete achievements. “We have managed to reduce muscle tremors significantly in trials with patients,” explains Andreas Schneider-Ickert, project manager for active implants and innovation manager.

The system is part of the EU-funded joint project “EXTEND.” A total of nine project partners from five different countries are working together to develop a versatile platform of distributed neural interfaces. The technology will be able to help people with neuromuscular disorders, such as tremors, or symptoms of paralysis. Even people with spinal cord injuries could benefit from this. The technology uses external controllers to link the implanted electrodes into an intelligent network. The components communicate with each other wirelessly, exchange data, detect muscle signals and send targeted stimuli into the muscles. Implanted systems are already being used medically to provide stimulation, but the current methods require complex surgical operations that are considerably stressful for patients.

Implants for the human-machine interface
A key element of EXTEND is the implants, which are made from biocompatible platinum-iridium and silicone and are injected into the muscle through a catheter. Just three centimeters long and barely a millimeter in diameter, the tiny implant has an electrode at each end that functions as either a sensor or an actuator. External electrodes sewn into a textile ribbon supply the module with energy. This sends pulsed alternating current through the muscle tissue to the implant. “What’s innovative about this is not only the intelligent interplay between control electronics, sensors and actuators, but also the principle of modulating the alternating current to transmit data,” explains Schneider-Ickert.

Once it has been implanted and started, the sensors register the first signs of muscle tremors and pass the information on to the external components. The controller evaluates the data and sends signals through the textile electrodes to stimulate the muscle. This closes a control circuit of intelligently networked sensor and actuator components that counteracts the tremor.

The stimulus signal is not strong enough to trigger a muscle contraction directly. It is the nervous system that plays the decisive role here. This registers the stimulation in the muscle tissue and responds by stopping the commands that trigger the muscle tremor. At least that is the theory — the finer details of the relationship between tremors and signals from the nervous system are yet to be researched. “In clinical trials, however, our method is working astonishingly well. Initial trials have shown that providing the patient with stimuli for one or two hours is enough to reduce tremor symptoms for a longer period of time,” says Schneider-Ickert.

Since tremors often occur in both arms and both legs, implants can be injected and external textile electrodes placed in all the affected muscle groups. This creates a distributed sensor network. The controllers can keep track of all the implanted and external electrodes at the same time and control them in coordination with each other. All this happens in real time, with the person experiencing no delay at all.

The technology being developed in the EXTEND joint project is just as functional as conventional implant systems, but minimally invasive and therefore easier to accept and better for everyday use. The basic concept originates from a Spanish project partner. Based in this concept, the researchers at Fraunhofer IBMT designed the electrodes and implantable components and produced and integrated them in the in-house cleanroom. The scientists have 25 years of expertise in neuroprosthetics and active implants.

Exoskeletons to prevent paraplegia
For tremor patients, EXTEND brings them the hope that their symptoms can be alleviated considerably. However, the technology platform could also help people with spinal cord injuries thanks to motorized exoskeletons. This is a possible because, in cases of paralysis, the nerve fibers are often not completely cut off. They can still transmit stimuli from the brain, albeit very weakly. The sensors register the activity and transmit it to the controller, which analyzes all the signals, works out what movement the person wants to perform and activates exactly the right prostheses to support the muscles in executing the movement.

Following initial successful tests, the concepts and technologies used in EXTEND have been steadily developed, miniaturized, optimized and subjected to further implementation studies. As a result, the project has now been completed with a successful proof of concept of the miniaturized full system in humans. Fraunhofer IBMT will use the knowledge gained from EXTEND to further develop its expertise in the field of neuromuscular and neural interfaces.

Textile-reinforced concrete components with a sustainable natural-fiber reinforcement possess sufficient bond and tensile load-bearing behavior for the utilization in construction. This has been verified by researchers at the Fraunhofer WKI in collaboration with Biberach University of Applied Sciences and the industrial partner FABRINO. In the future, textile-reinforced components with natural-fiber reinforcement could therefore replace conventionally reinforced concrete components and improve the environmental balance in the construction industry.

Non-metallic reinforcements for concrete elements are currently often made from various synthetically produced fibers - for example from glass or carbon fibers. An ecological alternative to synthetic fibers is provided by flax or other natural fibers. These are widely available and are more sustainable, due, amongst other things, to their renewable raw-material basis, the advantages regarding recycling, and the lower energy requirements during production. This is where the researchers from the Fraunhofer WKI and Biberach University of Applied Sciences, in collaboration with an industrial partner, became active. Their goal was to demonstrate that reinforcements made from textile fibers are just as suitable for utilization in construction as synthetic fibers.

"At the Fraunhofer WKI, we have produced leno fabrics from flax-fiber yarn using a weaving machine. In order to enhance sustainability, we tested a treatment of the flax yarns for improving the tensile strength, durability and adhesion which is ecologically advantageous compared to petro-based treatments," explained Jana Winkelmann, Project Manager at the Fraunhofer WKI. In the coating process, a commonly used petro-based epoxy resin was successfully replaced by a partially bio-based impregnation. A large proportion (56%) of the molecular structure of the utilized epoxy resin consists of hydrocarbons of plant origin and can therefore improve the CO₂ balance.

Textile reinforcements have a number of fundamental advantages. They exhibit, for example, significantly reduced corrodibility at the same or higher tensile strength than steel, with the result that the necessary nominal dimension of the concrete covering can be reduced. This often allows smaller cross-sections to be required for the same load-bearing capacity. Up to now, however, the load-bearing behavior of textile reinforcements made from natural fibers in concrete components has not been systematically investigated.

At Biberach University of Applied Sciences, researchers tested the bond and tensile load-bearing behavior as well as the uniaxial flexural load-bearing behavior of concrete components with textile reinforcement made from flax fibers. The scientists came to the conclusion that the natural-fiber-based textile-reinforced components with a bio-based impregnation are fundamentally suitable. The suitability was demonstrated by both a significant increase in the breaking load compared to non-reinforced and under-reinforced concrete components and in finely distributed crack patterns. The curves of the stress-strain diagrams could be divided into three ranges typical for reinforced expansion elements (State I - non-cracked, State IIa - initial cracking, and State IIb - final crack pattern). The delineation of the ranges becomes more pronounced as the degree of reinforcement increases.

As a whole, regionally or Europe-wide available, renewable natural fibers and a partially bio-based coating contribute towards an improvement of the CO₂ footprint of the construction industry. As a result, a further opportunity is being opened up for the energy- and raw-material-intensive construction industry in terms of meeting increasingly stringent environmental and sustainability requirements. "Textile-reinforced concretes enable lighter and more slender structures and therefore offer architectural leeway. We would like to continue our research into the numerous application possibilities of natural-fiber-reinforced concretes," said Christina Haxter, a staff member at the Fraunhofer WKI.

The project, which ran from 9th December 2020 to 31st December 2022, was funded by the German Federal Environmental Foundation (DBU).   

Photonic fibers borrow from butterfly wings to enable invisible, indelible sorting labels

Less than 15% of the 92 million tons of clothing and other textiles discarded annually are recycled—in part because they are so difficult to sort. Woven-in labels made with inexpensive photonic fibers, developed by a University of Michigan-led team, could change that.
 
“It’s like a barcode that’s woven directly into the fabric of a garment,” said Max Shtein, U-M professor of materials science and engineering and corresponding author of the study in Advanced Materials Technologies. “We can customize the photonic properties of the fibers to make them visible to the naked eye, readable only under near-infrared light or any combination.”

Ordinary tags often don’t make it to the end of a garment’s life—they may be cut away or washed until illegible, and tagless information can wear off. Recycling could be more effective if a tag was woven into the fabric, invisible until it needs to be read. This is what the new fiber could do.
 
Recyclers already use near-infrared sorting systems that identify different materials according to their naturally occurring optical signatures—the PET plastic in a water bottle, for example, looks different under near-infrared light than the HDPE plastic in a milk jug. Different fabrics also have different optical signatures, but Brian Iezzi, a postdoctoral researcher in Shtein’s lab and lead author of the study, explains that those signatures are of limited use to recyclers because of the prevalence of blended fabrics.

“For a truly circular recycling system to work, it’s important to know the precise composition of a fabric—a cotton recycler doesn’t want to pay for a garment that’s made of 70% polyester,” Iezzi said. “Natural optical signatures can’t provide that level of precision, but our photonic fibers can.”

The team developed the technology by combining Iezzi and Shtein’s photonic expertise—usually applied to products like displays, solar cells and optical filters—with the advanced textile capabilities at MIT’s Lincoln Lab. The lab worked to incorporate the photonic properties into a process that would be compatible with large-scale production.
 
They accomplished the task by starting with a preform—a plastic feedstock that comprises dozens of alternating layers. In this case, they used acrylic and polycarbonate. While each individual layer is clear, the combination of two materials bends and refracts light to create optical effects that can look like color. It’s the same basic phenomenon that gives butterfly wings their shimmer.

The preform is heated and then mechanically pulled—a bit like taffy—into a hair-thin strand of fiber. While the manufacturing process method differs from the extrusion technique used to make conventional synthetic fibers like polyester, it can produce the same miles-long strands of fiber. Those strands can then be processed with the same equipment already used by textile makers.

By adjusting the mix of materials and the speed at which the preform is pulled, the researchers tuned the fiber to create the desired optical properties and ensure recyclability. While the photonic fiber is more expensive than traditional textiles, the researchers estimate that it will only result in a small increase in the cost of finished goods.

“The photonic fibers only need to make up a small percentage—as little as 1% of a finished garment,” Iezzi said. “That might increase the cost of the finished product by around 25 cents—similar to the cost of those use-and-care tags we’re all familiar with.”

Shtein says that in addition to making recycling easier, the photonic labeling could be used to tell consumers where and how goods are made, and even to verify the authenticity of brand-name products. It could be a way to add important value for customers.

“As electronic devices like cell phones become more sophisticated, they could potentially have the ability to read this kind of photonic labeling,” Shtein said. “So I could imagine a future where woven-in labels are a useful feature for consumers as well as recyclers.”

The team has applied for patent protection and is evaluating ways to move forward with the commercialization of the technology.
The research was supported by the National Science Foundation and the Under Secretary of Defense for Research and Engineering.

Interview with Henning Wehland & Robert Kapferer, Circularity Germany

I'm a very curious guy by nature. That's why I offered to help out at a well-known hot dog station in Münster (Germany) this year, to draw attention to the shortage of staff in the gastronomy. I wrote an article about it on LinkedIn, which was in turn reacted to by Ines Chucholowius.
From her profile, I could see that she is a consultant for strategic marketing and communication in the textile industry. Not entirely serious, she offered me a job in her office. Like pushing a button, the pictures in my mind set in: Textile industry, exciting! Merchandising, contacts in the industry, collaborations, and I agreed to a short chat, at the end of which we spoke on the phone and arranged to meet.
 
She told me about her website TEXTINATION.de. And we were already involved in an exciting, heated exchange about perception and truth in the textile industry. Without further ado, we left it at that and I went home with a chunk of new information about an exciting field. Our dialogue on social media continued and eventually Ines offered me the chance to feed my die-hard curiosity with the support of TEXTINATION.de. I could write a blog on the site, about people, products, service providers, producers, startups or trends that interest me, to add to my half-knowledge about the textile industry.

Textile waste into the front ... new T-shirt out the back
During this exchange and a long brainstorming session, certain terms kept tickling my attention:
Circular economy, recycling, recyclable material loops. Circular Economy, Recycling, Recyclables. Even though there are many different definitions and some even distinguishing between different aspects: the former thought from waste that flows back into production as a secondary raw material, a more modern approach avoiding waste already in production - the general consensus is really only that circular economy is a cycle in which waste is used as a source for something new.

Sounds like useful additions for all areas of the manufacturing real economy to me. Ines introduced me to Robert Kapferer: He runs a startup called Circularity Germany in Hamburg. His company, founded in 2021 and consisting of Robert and another partner, is an offshoot of the Dutch-based company Circularity B.V. Its founder Han Hamers, with a degree in child psychology and a professional background in the textile dyeing industry, had the idea five years ago for a production facility that spins new yarn exclusively from textile production waste and old textiles turning it into T-shirts, polo shirts and sweatshirts.
Whether this works, and if so, how, is what I wanted to find out, and Ines and I arranged to meet Robert for a 90-minute online conference.

Robert, originally an industrial engineer, comes from a less sustainable industry. He worked for 11 years as managing director for AVECO Material und Service GmbH, where he was responsible for the workwear of more than 50,000 employees.

At the beginning of our conversation, he emphasizes that a moment in January 2021 changed his life and from then on, he wanted to dedicate himself to the topic of circular economy with all his might. That was when he met Han Hamers, who inspired him to found Circularity Germany. His enthusiasm and passion for the subject sound credible, and he begins to describe the differences between chemical and mechanical recycling methods. In summary, the mechanical process of shredding and the subsequent spinning shortens the fibers and thus restricts their properties for further processing. The advantage lies primarily in the comparatively uncomplicated, fast and more cost-efficient process. In the chemical variant, chemical waste remains, but the processed materials are broken down again into their basic building blocks in such a way that they have almost all the same properties as a so-called virgin raw material. Circularity Germany stands for the mechanical process.

And then comes the sentence that gets all our attention: "We've advanced a spinning technology so much that it relies exclusively on waste-based raw materials."
This sentence almost doesn't stand out because Robert still talks - quite excitingly - about the fact that they are planning a production and manufacturing facility where everything from knitting yarn to relatively fine thread can be spun and then further processed into fabric. And here Ines and I ask intensively: Essential requirements for industrial production still seem to be unresolved, and necessary processes are still in the planning stage. For example, the question of whether to work with pre-consumer or post-consumer waste. Pre-consumer waste is cutting waste from the production of clothes, which corresponds to about 10% of the processed material. Post-consumer waste we know as used textiles.

As long as production still takes place in India, Circularity currently uses mainly pre-consumer waste. These come exclusively from sewing factories in the Tirupur region in the south of India. When using used textiles, which exist in large quantities in Germany (according to a study, 28-40% of all garments produced are thrown away unworn), Circularity produces blended yarns of cotton and polyester. The company does not offer pure cotton yarns.

Textiles are treated with chemicals to varying degrees - workwear in particular cannot do without them. The fact that Han Hemers is also collecting used textile stocks from the Dutch army in order to reintroduce them renewed into the consumer cycle is therefore not reassuring. Military clothing has to be finished with all kinds of additives.

Therefor I ask how he can dispel doubts in a consumer’s mind like mine, with a healthy half-knowledge of mask deals and greenwashing, that a well-intentioned vision will be followed by a dark awakening. This concern cannot yet be resolved after the conversation.

We limit ourselves to what is planned: Robert has the dream of reversing the globalized process of textile production. He wants to end the decoupling of cotton growing regions and far-flung production such as Asia with subsequent shipping of ready-made goods to Europe. In the future, existing used textiles and/or cutting wastes are to be collected on site, recycled and processed locally into new textiles.

I believe him in having this dream. However, some of my questions about sustainability remain unanswered - which is why I have my doubts about whether the idea is currently capable of performing and competing.
What are the reasons for this? For one thing, I think it's always difficult to do necessary pioneering work. Especially when listening to smart comments at the regulars' table that large companies are already working intensively on the principle of circular economy. But sometimes, apart from the term "circular economy" and a vague commitment to it, not much remains.

Circularity Germany is committed to developing a technology based exclusively on waste. The interview points out that this also includes making production more environmentally friendly and eliminating transport routes, which further reduces the burden on the environment. When all the requirements for realizing this dream have been met and a product that is competitive in terms of both quality and price can be launched on the market, it is up to the consumer to decide. Here one would have the credible argument of sustainability and a socially and environmentally fair process. Circularity would then not have to worry about PR.

It needs to be given time and, above all, attention. But perhaps the industry should get involved right here and now, and invest in startups like this and make sure that problems are cleared out of the way. Because one thing has become clear to us in this conversation:

It could all be so simple. Circular economy is achievable, but the road there is still costly and rocky. That's why we wish Robert and his team every success and, above all, perseverance. Thank you for the interview.

Short and sweet: the profile of the company in the attached factsheet for download.

 

 

Nature works often with fiber composites. The construction principles of nature require little material and energy and thus ensure the survival of animals and plant species. Examples include wood, plant stalks, chitinous shells, bones or tissues such as tendons and skin. Mussel shells or spider silk are also composite tissues. We can take advantage of these principles to design and manufacture bio-based, sustainable fiber reinforced composites, which are currently in high demand. Bio-based fiber reinforced composites consist of natural fibers or cellulose fibers embedded in a bio-based matrix. The bio-based components offer properties comparable to those of commonly used glass fiber composites. The German Institutes of Textile and Fiber Research (DITF), together with Arburg GmbH + Co KG, are developing an energy- and material-efficient 3D printing process for manufacturing of such lightweight bio-based fiber composites.

In fiber composites, which occur naturally, reinforcing fibers such as collagen or cellulose fibrils are embedded in a matrix of lignin, hemicellulose or collagen. The fiber strands align with the stress patterns. Tissues are formed mostly via solution-based physio-chemical processes that take place at ambient temperature. Similar to nature, new 3D printing processes with continuous fiber reinforcement also allow the deposition of fiber strands in the right place (topology optimization) and in the appropriate direction in accordance to the load. However, natural fibers such as cellulose fibers are sensitive to higher temperatures. Therefore, they cannot be processed in the commonly employed thermoplastic 3D printing process.

The result of the research work is 3D-printed fiber composite components consisting of cellulose continuous fibers embedded in a cellulose-based matrix. Newly developed 3D-printing process enables to manufacture the composites at ambient temperature. This means that - as in nature - the material and component can be produced simultaneously in a single operation at ambient temperature.

The cellulose fiber strand is first stabilized with a binder for processing in the printer. The specially designed print head transforms the binder into a matrix with which the cellulose continuous fibers are encased. Since the cellulose fibers and the matrix have similar chemical structures, the composite component is particularly stable. The mechanical properties, such as breaking strength, are exceptionally good. The solution-based and energy-efficient manufacturing method developed by the research team can also be used in other composite materials manufacturing processes. It is particularly suitable for processing temperature-sensitive materials that are in high demand, such as natural or cellulose fibers.

The " CellLoes-3D-Druck" research project is funded by the German Federal Ministry of Education and Research as part of the "Biologisierung der Technik" ideas competition.