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(c) RMIT University
26.02.2024

Cooling down with Nanodiamonds

Researchers from RMIT University are using nanodiamonds to create smart textiles that can cool people down faster.

The study found fabric made from cotton coated with nanodiamonds, using a method called electrospinning, showed a reduction of 2-3 degrees Celsius during the cooling down process compared to untreated cotton. They do this by drawing out body heat and releasing it from the fabric – a result of the incredible thermal conductivity of nanodiamonds.

Published in Polymers for Advanced Technologies, project lead and Senior Lecturer, Dr Shadi Houshyar, said there was a big opportunity to use these insights to create new textiles for sportswear and even personal protective clothing, such as underlayers to keep fire fighters cool.

The study also found nanodiamonds increased the UV protection of cotton, making it ideal for outdoor summer clothing.

Researchers from RMIT University are using nanodiamonds to create smart textiles that can cool people down faster.

The study found fabric made from cotton coated with nanodiamonds, using a method called electrospinning, showed a reduction of 2-3 degrees Celsius during the cooling down process compared to untreated cotton. They do this by drawing out body heat and releasing it from the fabric – a result of the incredible thermal conductivity of nanodiamonds.

Published in Polymers for Advanced Technologies, project lead and Senior Lecturer, Dr Shadi Houshyar, said there was a big opportunity to use these insights to create new textiles for sportswear and even personal protective clothing, such as underlayers to keep fire fighters cool.

The study also found nanodiamonds increased the UV protection of cotton, making it ideal for outdoor summer clothing.

“While 2 or 3 degrees may not seem like much of a change, it does make a difference in comfort and health impacts over extended periods and in practical terms, could be the difference between keeping your air conditioner off or turning it on,” Houshyar said. “There’s also potential to explore how nanodiamonds can be used to protect buildings from overheating, which can lead to environmental benefits.”

The use of this fabric in clothing was projected to lead to a 20-30% energy saving due to lower use of air conditioning.

Based in the Centre for Materials Innovation and Future Fashion (CMIFF), the research team is made up of RMIT engineers and textile researchers who have strong expertise in developing next-generation smart textiles, as well as working with industry to develop realistic solutions.

Contrary to popular belief, nanodiamonds are not the same as the diamonds that adorn jewellery, said Houshyar. “They’re actually cheap to make — cheaper than graphene oxide and other types of carbon materials,” she said. “While they have a carbon lattice structure, they are much smaller in size. They’re also easy to make using methods like detonation or from waste materials.”

How it works
Cotton material was first coated with an adhesive, then electrospun with a polymer solution made from nanodiamonds, polyurethane and solvent.

This process creates a web of nanofibres on the cotton fibres, which are then cured to bond the two.

Lead researcher and research assistant, Dr Aisha Rehman, said the coating with nanodiamonds was deliberately applied to only one side of the fabric to restrict heat in the atmosphere from transferring back to the body.  

“The side of the fabric with the nanodiamond coating is what touches the skin. The nanodiamonds then transfer heat from the body into the air,” said Rehman, who worked on the study as part of her PhD. “Because nanodiamonds are such good thermal conductors, it does it faster than untreated fabric.”

Nanodiamonds were chosen for this study because of their strong thermal conductivity properties, said Rehman. Often used in IT, nanodiamonds can also help improve thermal properties of liquids and gels, as well as increase corrosive resistance in metals.

“Nanodiamonds are also biocompatible, so they’re safe for the human body. Therefore, it has great potential not just in textiles, but also in the biomedical field,” Rehman said.

While the research was still preliminary, Houshyar said this method of coating nanofibres onto textiles had strong commercial potential.
 
“This electrospinning approach is straightforward and can significantly reduce the variety of manufacturing steps compared to previously tested methods, which feature lengthy processes and wastage of nanodiamonds,” Houshyar said.

Further research will study the durability of the nanofibres, especially during the washing process.

Source:

Shu Shu Zheng, RMIT University

Photo: TheDigitalArtist, Pixabay
31.01.2024

“Smart nanocomposites” for wearable electronics, vehicles, and buildings

  • Small, lightweight, stretchable, cost-efficient thermoelectric devices signify a breakthrough in sustainable energy development and waste heat recovery.
  • Next-gen flexible energy harvesting systems will owe their efficiency to the integration of graphene nanotubes. They offer easy processability, stable thermoelectric performance, flexibility, and robust mechanical properties.
  • Nanocomposites have high market potential in manufacturing generators for medical and smart wearables, vehicles sensors, and efficient building management.

Around half of the world’s useful energy is wasted as heat due to the limited efficiency of energy conversion devices. For example, one-third of a vehicle’s energy dissipates as waste heat in exhaust gases. At the same time, vehicles contain more and more electronic devices requiring electrical energy.

  • Small, lightweight, stretchable, cost-efficient thermoelectric devices signify a breakthrough in sustainable energy development and waste heat recovery.
  • Next-gen flexible energy harvesting systems will owe their efficiency to the integration of graphene nanotubes. They offer easy processability, stable thermoelectric performance, flexibility, and robust mechanical properties.
  • Nanocomposites have high market potential in manufacturing generators for medical and smart wearables, vehicles sensors, and efficient building management.

Around half of the world’s useful energy is wasted as heat due to the limited efficiency of energy conversion devices. For example, one-third of a vehicle’s energy dissipates as waste heat in exhaust gases. At the same time, vehicles contain more and more electronic devices requiring electrical energy. As another example, lightweight wearable sensors for health and environmental monitoring are also becoming increasingly demanding. The potential to convert waste heat or solar energy into useful electrical power has emerged as an opportunity for more sustainable energy management. Convenient thermoelectric generators (TEGs) currently have only low effectiveness and a relatively large size and weight. Based on expensive or corrosion-vulnerable materials, they are rigid and often contain toxic elements.
 
Recently developed, easy-to-process, self-supporting and flexible nonwoven nanocomposite sheets demonstrate excellent thermoelectric properties combined with good mechanical robustness. A recent paper in ACS Applied Nano Materials described how researches combined a thermoplastic polyurethane (TPU) with TUBALLTM graphene nanotubes to fabricate a nanocomposite material capable of harvesting electrical energy from sources of waste heat.

Thanks to their high aspect ratio and specific surface area, graphene nanotubes provide TPU with electrical conductivity, making it possible to achieve high thermoelectrical performance while maintaining or improving mechanical properties. “Stiffness, strength, and tensile toughness were improved by 7, 25, and 250 times compared to buckypapers, respectively. Nanocomposite sheet shows low electrical resistivity of 7.5*10-3 Ohm×cm, high Young’s modulus of 1.8 GPa, failure strength of 80 MPa, and elongation at break of 41%,” said Dr. Beate Krause, Group Leader, Leibniz-Institut für Polymerforschung Dresden e. V.

Graphene nanotubes, being a fundamentally new material, provide an opportunity to replace current TEG materials with more environmentally friendly ones. The sensors powered by such thermoelectric generators could act as a “smart skin” for vehicles and buildings, providing sensoring capabilities to monitor performance and prevent potential issues before they lead to breakdowns, ensuring optimal operational efficiency. In aircraft, no-wire nanocomposites could serve as stand-alone sensors for monitoring deicing systems, eliminating the need for an extensive network of electrical cables. The high flexibility, strength, and reliability of graphene nanotube-enabled thermoelectric materials also extend their applications into the realm of smart wearable and medical devices.

Source:

Leibniz-Institut für Polymerforschung Dresden e. V. / OCSiAl

Ultra-thin smart textiles are being refined for their use in obstetric monitoring and will enable analysis of vital data via app for pregnancies. Photo: Pixabay, Marjon Besteman
24.07.2023

Intelligent Patch for Remote Monitoring of Pregnancy

During pregnancy, regular medical check-ups provide information about the health and development of the pregnant person and the child. However, these examinations only provide snapshots of their state, which can be dangerous, especially in high-risk cases. To enable convenient and continuous monitoring during this sensitive phase, an international research consortium is planning to further develop the technology of smart textiles. A patch equipped with highly sensitive electronics is meant to collect and evaluate vital data. In addition, the sensors will be integrated into baby clothing in order to improve the future of medical monitoring for newborns with the highest level of data security.

During pregnancy, regular medical check-ups provide information about the health and development of the pregnant person and the child. However, these examinations only provide snapshots of their state, which can be dangerous, especially in high-risk cases. To enable convenient and continuous monitoring during this sensitive phase, an international research consortium is planning to further develop the technology of smart textiles. A patch equipped with highly sensitive electronics is meant to collect and evaluate vital data. In addition, the sensors will be integrated into baby clothing in order to improve the future of medical monitoring for newborns with the highest level of data security.

The beginning of a pregnancy is accompanied by a period of intensive health monitoring of the baby and the pregnant person. Conventional prenatal examinations with ultrasound devices, however, only capture snapshots of the respective condition and require frequent visits to doctors, especially in high-risk pregnancies. With the help of novel wearables and smart textiles, researchers in the EU-funded project Newlife aim to enable continuous obstetric monitoring in everyday life.

One goal of the consortium, consisting of 25 partners, is the development of a biocompatible, stretchable, and flexible patch to monitor the progress of the pregnancy and the embryo. Similar to a band-aid, the patch will be applied to the pregnant person’s skin, continuously recording vital data using miniaturized sensors (e.g., ultrasound) and transmitting it via Bluetooth.

For some time now, modern medical technology has been relying on smart textiles and intelligent wearables to offer patients convenient, continuous monitoring at home instead of stationary surveillance. At the Fraunhofer Institute for Reliability and Microelectronics IZM, a team led by Christine Kallmayer is bringing this technology to application-oriented implementation, benefitting from the Fraunhofer IZM’s years of experience with integrating technologies into flexible materials. For the integrated patch, the researchers are using thermoplastic polyurethane as base materials, in which electronics and sensors are embedded. This ensures that the wearing experience is similar to that of a regular band-aid instead of a rigid film.

To ensure that the obstetric monitoring is imperceptible and comfortable for both pregnant individuals and the unborn child, the project consortium plans to integrate innovative MEMS-based ultrasound sensors directly into the PU material. The miniaturized sensors are meant to record data through direct skin contact. Stretchable conductors made of TPU material tracks will then transmit the information to the electronic evaluation unit and finally to a wireless interface, allowing doctors and midwives to view all relevant data in an app. In addition to ultrasound, the researchers are planning to integrate additional sensors such as microphones, temperature sensors, and electrodes.

Even after birth, the new integration technology can be of great benefit to medical technology: With further demonstrators, the Newlife team plans to enable the monitoring of newborns. Sensors for continuous ECG, respiration monitoring, and infrared spectroscopy to observe brain activity will be integrated into the soft textile of a baby bodysuit and a cap. "Especially for premature infants and newborns with health risks, remote monitoring is a useful alternative to hospitalization and wired monitoring. For this purpose, we must guarantee an unprecedented level of comfort provided by the ultra-thin smart textiles: no electronics should be noticeable. Additionally, the entire module has to be extremely reliable, as the smart textiles should easily withstand washing cycles," explains Christine Kallmayer, project manager at Fraunhofer IZM.

For external monitoring of the baby's well-being, the project is also researching ways to use camera data and sensor technology in the baby's bed. Once the hardware basis of the patch, the textile electronics, and the sensor bed is built and tested, the project partners will take another step forward. Through cloud-based solutions, AI and machine learning will be used to simplify the implementation for medical staff and ensure the highest level of data security.

The Newlife project is coordinated by Philips Electronics Nederland B.V. and will run until the end of 2025. It is funded by the European Union under the Horizon Europe program as part of Key Digital Technologies Joint Undertaking under grant number 101095792 with a total of 18.7 million euros.

Source:

Fraunhofer Institute for Reliability and Microintegration IZM

Thread-like pumps can be woven into clothes (c) LMTS EPFL
27.06.2023

Thread-like pumps can be woven into clothes

Ecole Polytechnique Fédérale de Lausanne (EPFL) researchers have developed fiber-like pumps that allow high-pressure fluidic circuits to be woven into textiles without an external pump. Soft supportive exoskeletons, thermoregulatory clothing, and immersive haptics can therefore be powered from pumps sewn into the fabric of the devices themselves.

Many fluid-based wearable assistive technologies today require a large and noisy pump that is impractical – if not impossible – to integrate into clothing. This leads to a contradiction: wearable devices are routinely tethered to unearable pumps. Now, researchers at the Soft Transducers Laboratory (LMTS) in the School of Engineering have developed an elegantly simple solution to this dilemma.

Ecole Polytechnique Fédérale de Lausanne (EPFL) researchers have developed fiber-like pumps that allow high-pressure fluidic circuits to be woven into textiles without an external pump. Soft supportive exoskeletons, thermoregulatory clothing, and immersive haptics can therefore be powered from pumps sewn into the fabric of the devices themselves.

Many fluid-based wearable assistive technologies today require a large and noisy pump that is impractical – if not impossible – to integrate into clothing. This leads to a contradiction: wearable devices are routinely tethered to unearable pumps. Now, researchers at the Soft Transducers Laboratory (LMTS) in the School of Engineering have developed an elegantly simple solution to this dilemma.

“We present the world’s first pump in the form of a fiber; in essence, tubing that generates its own pressure and flow rate,” says LMTS head Herbert Shea. “Now, we can sew our fiber pumps directly into textiles and clothing, leaving conventional pumps behind.” The research has been published in the journal Science.

Lightweight, powerful…and washable
Shea’s lab has a history of forward-thinking fluidics. In 2019, they produced the world’s first stretchable pump.

“This work builds on our previous generation of soft pump,” says Michael Smith, an LMTS post-doctoral researcher and lead author of the study. “The fiber format allows us to make lighter, more powerful pumps that are inherently more compat-ible with wearable technology.”

The LMTS fiber pumps use a principle called charge injection electrohydrodynamics (EHD) to generate a fluid flow without any moving parts. Two helical electrodes embedded in the pump wall ionize and accelerate molecules of a special non-conductive liquid. The ion movement and electrode shape generate a net forward fluid flow, resulting in silent, vibration-free operation, and requiring just a palm-sized power supply and battery.

To achieve the pump’s unique structure, the researchers developed a novel fabrication technique that involves twisting copper wires and polyurethane threads together around a steel rod, and then fusing them with heat. After the rod is removed, the 2 mm fibers can be integrated into textiles using standard weaving and sewing techniques.

The pump’s simple design has a number of advantages. The materials required are cheap and readily available, and the manufacturing process can be easily scaled up. Because the amount of pressure generated by the pump is directly linked to its length, the tubes can be cut to match the application, optimizing performance while minimizing weight. The robust design can also be washed with conventional detergents.

From exoskeletons to virtual reality
The authors have already demonstrated how these fiber pumps can be used in new and exciting wearable technologies. For example, they can circulate hot and cold fluid through garments for those working in extreme temperature environments or in a therapeutic setting to help manage inflammation; and even for those looking to optimize athletic performance.

“These applications require long lengths of tubing anyway, and in our case, the tubing is the pump. This means we can make very simple and lightweight fluidic circuits that are convenient and comfortable to wear,” Smith says.

The study also describes artificial muscles made from fabric and embedded fiber pumps, which could be used to power soft exoskeletons to help patients move and walk.

The pump could even bring a new dimension to the world of virtual reality by simulating the sensation of temperature. In this case, users wear a glove with pumps filled with hot or cold liquid, allowing them to feel temperature changes in response to contact with a virtual object.

Pumped up for the future
The researchers are already looking to improve the performance of their device. “The pumps already perform well, and we’re confident that with more work, we can continue to make improvements in areas like efficiency and lifetime,” says Smith. Work has already started on scaling up the production of the fiber pumps, and the LMTS also has plans to embed them into more complex wearable devices.

“We believe that this innovation is a game-changer for wearable technology,” Shea says.

More information:
EPFL Fibers exoskeleton wearables
Source:

Celia Luterbacher, School of Engineering | STI

Aerogel (c) Outlast Technologies GmbH
31.01.2023

Aerogel: Frozen Smoke for Clothing and Work Safety

Comprised of up to 99.8 percent air, aerogel is the lightest solid in the world. The material, which is also called “frozen smoke” due to its appearance and physical properties, exhibits extremely low heat conductivity which exceeds other insulations many times over. This is why NASA has already been using aerogel for aerospace projects for many years.

Despite this, it has not been possible to bind the material to textiles in a high concentration and enable straightforward further processing over the roughly 90-year history of the material. Outlast Technologies GmbH has developed an innovative process - a patent has already been filed for -  for permanently adhering large amounts of aerogel to different media, like nonwoven fabric, felt and composites materials. Their original properties are retained throughout, so they can easily be further processed using conventional production methods.

Comprised of up to 99.8 percent air, aerogel is the lightest solid in the world. The material, which is also called “frozen smoke” due to its appearance and physical properties, exhibits extremely low heat conductivity which exceeds other insulations many times over. This is why NASA has already been using aerogel for aerospace projects for many years.

Despite this, it has not been possible to bind the material to textiles in a high concentration and enable straightforward further processing over the roughly 90-year history of the material. Outlast Technologies GmbH has developed an innovative process - a patent has already been filed for -  for permanently adhering large amounts of aerogel to different media, like nonwoven fabric, felt and composites materials. Their original properties are retained throughout, so they can easily be further processed using conventional production methods.

The fabrics sold under the Aersulate name are only 1 to 3 mm thick and achieve very high insulation values which are largely retained even under pressure and in moist conditions. Despite their high performance, they are still soft and can be used for shoes, clothing and work safety products, as well as for sleeping bags and technical applications.
 
“Thanks to its extraordinary physical properties, NASA has already been using aerogel for many years,” remarked Volker Schuster, Head of Research and Development at Outlast Technologies. “For example, for the insulation of its Mars rovers and for capturing dust from the tail of a comet during the Stardust mission,” he continued. Since the development of aerogel by American scientist and chemical engineer Samuel Stephens Kistler in 1931, no-one had been able to apply the versatile material to textiles in large amounts without changing their original properties, despite intensive research. This means that the products were often not only very rigid, but made processing with conventional production methods impossible due to their high degree of dust abrasion. With the newly developed Aersulate technology, which was presented for the first time in June 2022, the Heidenheim-based specialist for textile thermoregulation is opening a different chapter in insulation history.

High-performance insulation just 1 to 3 mm thick
“The consistency of aerogel can be best described as liquid dust particles which spread uncontrollably throughout a room within seconds thanks to their minimal thickness,” explained Schuster. “This is why processing is a big challenge.” Outlast Technologies has managed, after a development period of around five years, to bring an innovative process involving the adhering of aerogel between multiple layers of material to market maturity. Depending on the area of application, nonwoven fabric, felt and different composite materials can be used as the media. What is special here is that the properties of the respective textiles are not adversely affected by the Aersulate technology, meaning that they can easily be further processed with conventional means and under industrial conditions despite their acquired thermal properties.
 
As a silicate-based solid, aerogel is obtained from natural quartz sand, yet exhibits a density over 1,000 times lower than glass manufactured from the same raw material. The extraordinary thermo-insulating properties of the material are thanks to its extremely porous structure, which enables it to be composed of up to 99.8 percent air.
 
“One liter of aerogel weighs just 50 g,” explained Schuster. “Just 10 g of the material has the same surface area as a soccer field, though.” Thanks to these properties, Aersulate textiles exceed all other previously known insulation materials in terms of performance, despite the fact that they are only 1 to 3 mm thick. Tests carried out by the German Institute for Textile and Fiber Research in Denkendorf (DITF) using the Alambeta method showed that the thermal resistance of an Aersulate fleece is more than double that of a conventional fleece of the same thickness. Add to this the fact that the thermo-insulating properties of Aersulate products remain high despite pressure and wetness, while they decrease enormously with other conventional materials like felt and polyurethane foam (PU) under these conditions.

Work safety and functional clothing with Aersulate
Thanks to the textile medium, thin Aersulate products are especially suitable for the shoe and clothing industry, as well as all areas of work safety. The user benefits from different properties, depending on the intended use. “With a glove made of Aersulate just 1 mm thick, you can put your hand into boiling water without being scalded, for example,” explained Schuster. “The material’s extremely hydrophobic properties play quite literally into our hands here.” In the case of knee patches on work and functional pants, as well as shoes and soles, on the other hand, the material properties also become relevant when compression occurs. This is because the thermo-insulation properties of other materials would be reduced little by little due to moisture from the outside and sweat from the inside on the one hand, and by the continual influence of body weight on the other.
          
In addition to the human body, luggage and technical devices can also be protected from extreme temperatures and the effects of weather with Aersulate. For this purpose, corresponding cell phone or equipment pockets could be sewn into garments, for example, to maintain their battery life even at very cold outside temperatures and to safeguard the devices from overheating in case of high heat exposure. “With the broad range of possible textile medium materials, Aersulate is suitable for all applications requiring high thermal resistance on the one hand, where only a little space is available and both compression and moisture can be expected on the other,” said Schuster in summary.

Source:

Outlast Technologies / Textination

North Carolina State University
17.01.2023

Embroidery as Low-Cost Solution for Making Wearable Electronics

Embroidering power-generating yarns onto fabric allowed researchers to embed a self-powered, numerical touch-pad and movement sensors into clothing. The technique offers a low-cost, scalable potential method for making wearable devices.

“Our technique uses embroidery, which is pretty simple – you can stitch our yarns directly on the fabric,” said the study’s lead author Rong Yin, assistant professor of textile engineering, chemistry and science at North Carolina State University. “During fabric production, you don’t need to consider anything about the wearable devices. You can integrate the power-generating yarns after the clothing item has been made.”

Embroidering power-generating yarns onto fabric allowed researchers to embed a self-powered, numerical touch-pad and movement sensors into clothing. The technique offers a low-cost, scalable potential method for making wearable devices.

“Our technique uses embroidery, which is pretty simple – you can stitch our yarns directly on the fabric,” said the study’s lead author Rong Yin, assistant professor of textile engineering, chemistry and science at North Carolina State University. “During fabric production, you don’t need to consider anything about the wearable devices. You can integrate the power-generating yarns after the clothing item has been made.”

In the study published in Nano Energy, researchers tested multiple designs for power-generating yarns. To make them durable enough to withstand the tension and bending of the embroidery stitching process, they ultimately used five commercially available copper wires, which had a thin polyurethane coating, together. Then, they stitched them onto cotton fabric with another material called PTFE.

“This is a low-cost method for making wearable electronics using commercially available products,” Yin said. “The electrical properties of our prototypes were comparable to other designs that relied on the same power generation mechanism.”

The researchers relied on a method of generating electricity called the “triboelectric effect,” which involves harnessing electrons exchanged by two different materials, like static electricity. They found the PTFE fabric had the best performance in terms of voltage and current when in contact with the polyurethane-coated copper wires, as compared to other types of fabric that they tested, including cotton and silk. They also tested coating the embroidery samples in plasma to increase the effect.

“In our design, you have two layers – one is your conductive, polyurethane-coated copper wires, and the other is PTFE, and they have a gap between them,” Yin said. “When the two non-conductive materials come into contact with each other, one material will lose some electrons, and some will get some electrons. When you link them together, there will be a current.”
Researchers tested their yarns as motion sensors by embroidering them with the PTFE fabric on denim. They placed the embroidery patches on the palm, under the arm, at the elbow and at the knee to track electrical signals generated as a person moves. They also attached fabric with their embroidery on the insole of a shoe to test its use as a pedometer, finding their electrical signals varied depending on whether the person was walking, running or jumping.

Lastly, they tested their yarns in a textile-based numeric keypad on the arm, which they made by embroidering numbers on a piece of cotton fabric, and attaching them to a piece of PTFE fabric. Depending on the number that the person pushed on the keypad, they saw different electrical signals generated for each number.

“You can embroider our yarns onto clothes, and when you move, it generates an electrical signal, and those signals can be used as a sensor,” Yin said. “When we put the embroidery in a shoe, if you are running, it generates a higher voltage than if you were just walking. When we stitched numbers onto fabric, and press them, it generates a different voltage for each number. It could be used as an interface.”

Since textile products will inevitably be washed, they tested the durability of their embroidery design in a series of washing and rubbing tests. After hand washing and rinsing the embroidery with detergent, and drying it in an oven, they found no difference or a slight increase in voltage. For the prototype coated in plasma, they found weakened but still superior performance compared with the original sample. After an abrasion test, they found that there was no significant change in electrical output performance of their designs after 10,000 rubbing cycles.

In future work, they plan to integrate their sensors with other devices to add more functions.
“The next step is to integrate these sensors into a wearable system,” Yin said.

The study, “Flexible, durable and washable triboelectric yarn and embroidery for self-powered sensing and human-machine interaction,” was published online in Nano Energy. Co-authors included Yu Chen, Erdong Chen, Zihao Wang, Yali Ling, Rosie Fisher, Mengjiao Li, Jacob Hart, Weilei Mu, Wei Gao, Xiaoming Tao and Bao Yang. Funding was provided by North Carolina State University through the NC State Faculty Research & Professional Development Fund and the NC State Summer REU program.

 

Source:

North Carolina State University, Rong Yin, Laura Oleniacz

Photo: pixabay
10.08.2021

Stand-up paddle board made from renewable lightweight mater

Stand-up paddling has become a popular sport. However, conventional surfboards are made of petroleum-based materials such as epoxy resin and polyurethane.

Researchers at the Fraunhofer Institute for Wood Research, Wilhelm-Klauditz-Institut, WKI, want to replace plastic boards with sustainable sports equipment: They are developing a stand-up paddle board that is made from one hundred percent renewable raw materials. The ecological lightweight material can be used in many ways, such as in the construction of buildings, cars and ships.

Stand-up paddling has become a popular sport. However, conventional surfboards are made of petroleum-based materials such as epoxy resin and polyurethane.

Researchers at the Fraunhofer Institute for Wood Research, Wilhelm-Klauditz-Institut, WKI, want to replace plastic boards with sustainable sports equipment: They are developing a stand-up paddle board that is made from one hundred percent renewable raw materials. The ecological lightweight material can be used in many ways, such as in the construction of buildings, cars and ships.

Stand-up paddling (SUP) is a sport that is close to nature, but the plastic boards are anything but environmentally friendly. As a rule, petroleum-based materials such as epoxy resin, polyester resin, polyurethane and expanded or extruded polystyrene are used in combination with fiberglass and carbon fiber fabrics to produce the sports equipment. In many parts of the world, these plastics are not recycled, let alone disposed of correctly. Large quantities of plastic end up in the sea and collect in huge ocean eddies. For Christoph Pöhler, a scientist at Fraunhofer WKI and an avid stand-up paddler, this prompted him to think about a sustainable alternative. In the ecoSUP project, he is driving the development of a stand-up paddle board that is made from 100 percent renewable raw materials and which is also particularly strong and durable. The project is funded by the German Federal Ministry of Education and Research (BMBF). The Fraunhofer Center for International Management and Knowledge Economy IMW is accompanying the research work, with TU Braunschweig acting as project partner.

Recovering balsa wood from rotor blades
“In standard boards, a polystyrene core, which we know as styrofoam, is reinforced with fiberglass and sealed with an epoxy resin. We, instead, use bio-based lightweight material,” says the civil engineer. Pöhler and his colleagues use recycled balsa wood for the core. This has a very low density, i.e. it is light yet mechanically stressable. Balsa wood grows mainly in Papua New Guinea and Ecuador, where it has been used in large quantities in wind turbines for many years – up to six cubic meters of the material can be found in a rotor blade. Many of the systems are currently being disconnected from the grid. In 2020 alone, 6000 were dismantled. A large proportion of this is burnt. It would make more sense to recover the material from the rotor blade and recycle it in accordance with the circular economy. “This was exactly our thinking. The valuable wood is too good to burn,” says Pöhler.

Since the entire sandwich material used in conventional boards is to be completely replaced, the shell of the ecological board is also made from one hundred percent bio-based polymer. It is reinforced with flax fibers grown in Europe, which are characterized by very good mechanical properties. To pull the shell over the balsa wood core, Pöhler and his team use the hand lay-up and vacuum infusion processes. Feasibility studies are still underway to determine the optimal method. The first demonstrator of the ecological board should be available by the end of 2022. “In the interests of environmental protection and resource conservation, we want to use natural fibers and bio-based polymers wherever it is technically possible. In many places, GFRP is used even though a bio-based counterpart could do the same,” Pöhler sums up.

Patented technology for the production of wood foam
But how is it possible to recover the balsa wood from the rotor blade — after all, it is firmly bonded to the glass-fiber reinforced plastic (GFRP) of the outer shell? First, the wood is separated from the composite material in an impact mill. The density differences can be used to split the mixed-material structures into their individual components using a wind sifter. The balsa wood fibers, which are available as chips and fragments, are then finely ground. “We need this very fine starting material to produce wood foam. Fraunhofer WKI has a patented technology for this,” explains the researcher. In this process, the wood particles are suspended to form a kind of cake batter and processed into a light yet firm wood foam that holds together thanks to the wood’s own binding forces. The addition of adhesive is not required. The density and strength of the foam can be adjusted. “This is important because the density should not be too high. Otherwise, the stand-up paddle board would be too heavy to transport.”

Initially, the researchers are focusing on stand-up paddle boards. However, the hybrid material is also suitable for all other boards, such as skateboards. The future range of applications is broad: For example, it could be used as a facade element in the thermal insulation of buildings. The technology can also be used in the construction of vehicles, ships and trains.

Photocredits: Hohenstein
01.09.2020

Research Projects of the Zuse Community: Think about Recycling when Designing …

How applied research in cooperation with industry can lead to high-quality recycling solutions is explained by the Zuse community with its "Design for Recycling" series.

How applied research in cooperation with industry can lead to high-quality recycling solutions is explained by the Zuse community with its "Design for Recycling" series.

Artificial Turf of the Future
Textiles are much more than just clothes. The industry is a key customer for both synthetic and natural fibers. However, their textile products are often close to the consumer - this applies, for example, to the leisure industry or sports field construction, as is the case with artificial turf.
     
On sports fields, textiles are, so to speak, trampled underfoot, namely when playing on artificial turf. In Germany alone there are around 5,000 artificial turf pitches registered for football. But under the green stubble hides a heavy burden - for clubs and the environment. According to information from the IAKS Germany trade association, around 5 kg of granulate per square meter of artificial turf is infilled in Germany, and this figure is likely to be considerably higher in other countries. "In the case of artificial turf with a fiber length of 42 mm, only 12 mm look out of the mass of infill materials that have been applied to the surface," Dr. Ulrich Berghaus of Morton Extrusionstechnik GmbH, a leading manufacturer of artificial turf, explains. Nowadays, a new pitch is calculated to contain almost 50 percent of the old pitch - as infill material. But as a microplastic this can cause problems - alternatives have to be found. Together with the Aachen Institute for Floor Systems (TFI), Morton Extrusionstechnik is working on the artificial turf of the future, which can do without problematic infill materials.

The researchers at the TFI are now called upon to ensure that the nubs of the artificial turf will hold well in the carrier material in future, even without polyurethane and latex. "Ideally, artificial turf would be made of just one polymer," TFI project manager Dirk Hanuschik says. Because, similar to food packaging, inseparable material composites are poison for high-quality recycling. Hanuschik and his team are therefore researching with their industrial partner into an artificial turf design that does not require any polyurethane or latex for the backing of the carrier material. In a thermobonding facility, the artificial turf nubs are to be melted directly onto the base material, not glued on. Nevertheless, a durability of around 12-15 years is the goal - as with artificial turf laid today. He can test the new materials on the industrial coating plant, which is on a smaller scale at the TFI. The first production plant is scheduled to go into operation as early as the middle of next year.
     
"The practical project of the TFI is an excellent example of how industrial research from the Zuse community creates concrete benefits for people through sustainable recycling management. Research on 'Design for Recycling' is the focus of many of our institutes. Their close cooperation with companies and their interdisciplinary approach offer the best conditions for further innovations," explains the President of the Zuse Community, Prof. Martin Bastian.


Recycling in the Fashion Industry
Recycling is more than just a trend. In the future, fashion should increasingly include useful recycling: People in Germany buy an average of 26 kg of textiles per capita per year, including 12-15 kg of clothing. Given these large quantities, high-quality recycling is a major challenge. Improved recycling includes a circular economy that thinks about the "life after", i.e. the next or renewed product, already when designing products. A current research project of the Zuse community shows how this can work for clothing.
     
Beverage bottles made of the plastic PET are already ideally suited for recycling, and not only for packaging, because of their purity of type. Under the motto "From the fiber to the fiber", this is what the applied research in the joint project DiTex is using for rental linen. The fibers used come from recycled PET bottles, and the rented linen itself is to be recycled back into linen after its first life cycle.

"Rented linen is also well suited to the 'Design for Recycling' concept because its use can be precisely tracked, which provides optimum conditions for recycling," project manager Dr. Anja Gerhardts from the Hohenstein Research Institute explains. The institute from Baden-Württemberg is responsible for textile testing and product specifications in the project initiated and coordinated by the Institute for Ecological Economic Research (IÖW). For benefit rather than ownership, the partners in the alliance are developing a recyclable line of bed linen, as well as polo and business shirts. The shirts will serve as uniforms for police and rescue services.

Intelligent label stores information
The laundry is equipped with a digital tracking ID throughout the entire usage cycle. This "intelligent" label stores information such as fiber origin, material composition and composition of the textile. This enables recycling companies to sort the products better, increase the recycling share and upgrade them. Numerous washing trials are now being carried out at Hohenstein to test how well the tracking tool is performing and what the tensile strength, degree of whiteness, color quality, durability and wearing comfort of the textiles are when they are washed, spun and dried up to 200 times in commercial textile services. "In DiTex we bring users, procurers and recyclers of textiles to one table to make recyclable product design a reality", Anja Gerhardts explains.

"Practical research on fibers and textiles is one of the core competences of many of our institute, be it for industrial technical products or consumer-oriented products. Projects like DiTex show innovative solutions for design for recycling. Thanks to the interdisciplinary approach in our association, other industries can also learn from such solutions," explains Dr. Annette Treffkorn, managing director of the Zuse community.

Source:

Zuse-Gemeinschaft