Today's KNOWLEDGE Share : Kyoto University successfully synthesizes graphene nanoribbons for use as rare-earth-free, inexpensive, lightweight, & rustproof carbon magnets

Today's KNOWLEDGE Share

Kyoto University successfully synthesizes graphene nanoribbons for use as rare-earth-free, inexpensive, lightweight, and rustproof carbon magnets

Professor Hiroshi Sakaguchi and Associate Professor Takahiro Kojima of the Institute of Advanced Energy, Kyoto University, in collaboration with the National University of Singapore and the University of California, Berkeley (USA), announced that they have successfully developed carbon magnets. By designing a precursor molecule and using a unique stereoregularly controlled synthesis method, they succeeded in synthesizing graphene nanoribbons (GNRs), which exhibited magnetic properties by localizing spins of the same orientation on only one side. The GNRs were named "Janus GNRs" after Janus, the two-faced god in Greek mythology. Theoretical calculations showed that the magnetic strength of the GNRs can be tuned via molecular design. These results are expected to lead to the development of lightweight, rustproof, rare-earth-free magnets and were published in the January 9 issue of the international journal Nature.

The origin of a magnet is the spin in matter, and the direction and magnitude of the electron spin reflect the polarity and strength of the magnet. For example, if the upward and downward spins are equal in amount, the material will not show magnetism. Magnets are used in many products such as HDDs and medical equipment. However, current magnets are made of metals, which are highly stable but heavy and undergo rusting. Further, neodymium magnets use rare-earth elements, which encounter supply risks.

In response to this, research has been conducted since the 1980s to produce magnets using carbon, which is inexpensive and abundant. However, the low spin magnitude (weak magnetic force) and stability of carbon have limited its application.

Recently, it was reported that graphene cut into strips with zigzag ends (GNRs) can be theoretically used as magnets. The next step was experimental synthesis, which confirmed spin localization at both ends of the long sides of the strips. However, it was found that the spins at both ends were opposite and canceled each other out, preventing the strips from becoming magnets. It was also predicted that to achieve magnetic properties, the GNRs need to be asymmetric, with one of the sides not having a zigzag structure.

In this international collaboration, the Kyoto University research team designed a precursor molecule (Z-type asymmetric precursor) whose final morphology was an asymmetric zigzag-edged GNR. The team used a unidirectional surface synthesis method that was developed in 2023. Because they are generally unstable in air, GNRs are synthesized as precursors and then linked and assembled in an ultrahigh-vacuum cauldron.

When the precursor molecules are asymmetric, three types of linkage methods can be used: isotactic (linking in one direction), syndiotactic (linking in alternating directions), and atactic (linking in random directions). Asymmetric zigzag-edged GNRs require isotactic linking, and the unidirectional surface synthesis method made the preparation of the GNRs possible.

Specifically, the synthesis method deforms the precursor molecules on the metal substrate, causing them to self-assemble, polymerize, and undergo a dehydrogenative fused-ring reaction. The prepared samples were analyzed by the research team at the National University of Singapore using scanning tunneling microscopy and atomic force microscopy. They confirmed that asymmetric zigzag-edged GNRs with regular protrusions on only one side were synthesized at the atomic level. In addition, electronic state mapping using scanning tunneling spectroscopy confirmed the localization of electron spins on only one side.

The research team at the University of California performed theoretical calculations on the electron spin density of the asymmetric zigzag-edged GNRs based on the assumption that the GNRs are carbon magnets. The results agreed with the experimental values, proving that the synthesized GNRs were indeed magnets. Furthermore, the team systematized the theory further and found that magnetism can be freely controlled by varying the spacing of the opposite projections of the spins.

source: The Graphene Council

Today's KNOWLEDGE Share : Frozen Layer Thickness

Today's KNOWLEDGE Share

 When trying to model Injection Molding one has to determine the transient frozen layer thickness.

And it is more tricky than most might think.

For amorphous polymers the best transition temperature would be available straight from the PvT data and will even include the important pressure dependence. It will however not include any cooling rate dependence and Tg is extremely sensitive to cooling rate, as people observe daily with DSC

PvT is essentially measured in a quiescent state close to thermodynamic equilibrium (very slow heat/cool rates).

For semi-crystalline materials the problem is worse. We need to capture the crystallization temperature which is pressure dependent also (that can be seen in PvT) but extremely dependent on cooling rate (crystallization kinetics aspects).

Furthermore, the strong nucleation effect of shear-stress close to the outer layers will dramatically increase, locally, this transition temperature. Which means the transition temperature will be very different from skin to core.

In essence, there is not such a thing as ONE no flow temperature or transition temperature.

To preserve mass balance in molding simulation it will also be of key importance to perfectly "sync" the phase change for all physical properties (PvT, thermal data, viscosity,...).

We still have a long way to go to fully capture this complex physics in our beloved commercial software tools.

The best attempt I know of, was an old Research Release version of Moldflow, work I was involved in) including explicit crystallization kinetics and implementing "dynamic" PvT (transition zone driven by real kinetics), with full sync of all other variables.

source: Vito leo

Greece orders 8 Airbus H215 helicopters to combat forest fires

Airbus Helicopters has signed a contract with the Hellenic Ministry of Climate Crisis and Civil Protection for the purchase of 8 H215 helicopters (with an option for 2 additional aircraft) to support the combat of wildfires in the country following a tender conducted by the Project Preparation Facility of Growthfund (the National Fund of Greece) on behalf of the Ministry. This contract is supported by 2 European funds and aligns with the Ministry’s Aegis Programme aimed at enhancing the capabilities of the Civil Protection forces. The contract will be based on a “government owned contractor operated” (GO-CO) model for which Airbus Helicopters will be partnering with experienced H215 firefighting operators, Airtelis and SAF Hélicoptères, for the technical and operational support. 

“The signing of the contract for the purchase of new H215 helicopters represents an important step in our efforts to mitigate the devastating consequences of the climate crisis in our country,” said Panagiotis Stampoulidis, Deputy CEO of Growthfund, about the significance of the project. “This is the largest contract signed under the ‘Aegis’ National Programme to bolster the Civil Protection mechanism in Greece with modern equipment, and we are delighted that the Project Preparation Facility of Growthfund swiftly concluded this tender with transparency and efficiency.”

“Wildfires have burned on average 3 to 5 million square kilometres globally in recent years with significant environmental consequences. It is an honour to have been selected to support the combat, with our H215 helicopters, that Greek communities face every year,” said Bruno Even, CEO of Airbus Helicopters. “The H215 is used around the world for firefighting missions with its ability to drop more than 4 tonnes of water at a time. Relying on experienced operators, such as Airtelis and SAF Aerogroup, is exactly what the French Securité Civile does. Airbus Helicopters has been a long-standing provider of helicopters for essential missions in the country and together with our GO-CO partners, we are sure that the H215 will be a vital and reliable asset,” he added.

SAF Aerogroup specialises in complex helicopter operations like mountain rescue, air medical services, firefighting and humanitarian/logistic missions, demonstrated by their 2024 H215 RescEU deployment to Greece. The group also manages high-precision lifting, maintenance and pilot/technician training, offering comprehensive high-value air services to governmental and international organisations. Similarly, Airtelis, a French operator based in the South of France with over 60 years of experience stemming from its parent company RTE, has broadened its focus beyond power grid support to include emergency response, notably firefighting, for a wider range of national and international clients.  

Airbus Helicopters has been a long-standing partner in Greece since the early 2000s in both the civil and parapublic and military sectors. The Hellenic Fire Brigade operates 2 Super Pumas and the Hellenic Air Force operates 12 Super Pumas. The Super Puma ecosystem in the country will benefit from the support activities and training of technicians and pilots foreseen by the contract.

Cover photo: Greece orders 8 Airbus H215 helicopters to combat forest fires

source: Airbus /jeccomposites.com

Röhm Starts Production of First C2-Based MMA Plant in the US

Röhm, one of the world’s leading chemical manufacturers of methacrylates, announces the successful start-up of its new plant in Bay City, Texas, USA, implementing its proprietary C2-based LiMA technology on a large industrial scale.

 

The start-up of the Bay City plant is a milestone in the company’s history and the starting point for us to deliver the next generation of MMA based on our proprietary LiMA technology, which not only benefits the environment but also increases the security of supply for this growing market,” said Dr. Hans Bohnen, CEO of Röhm.

I am very grateful for the hard work of our partners and suppliers who have played an important role in bringing this new technology to the market. The strong demand for our products has already led to commitments from many long-term customers. This is a strong demonstration of the benefits that our new MMA technology brings to all stakeholders.”

 

Once fully operational, the Röhm Bay City plant will produce 250,000 metric tons of MMA per year. Based on the raw materials ethylene, natural gas and methanol, the new technology offers higher product yields, lower energy consumption, and less water and waste impact compared to conventional production routes.

 

"Our investment in Röhm reflects Advent's commitment to helping develop and grow innovative, world-class businesses and solutions," said Ron Ayles, Managing Partner of Advent International. "The Bay City facility, with its new LiMA technology, brings a sustainable, high-quality product to the growing U.S. MMA market, which is currently undersupplied. We made the investment at the right time and place, and we are now the only C2 producer in the U.S. We look forward to continuing our partnership with Röhm to further develop Röhm's position as the inventor and technology leader of global methacrylates."

 

Röhm's customers have already shown strong interest in its MMA produced via its proprietary C2 process. The Bay City facility is ideally located to serve both the U.S. and global markets. "Demand has exceeded our initial expectations. In the coming weeks, we will be working to increase production rates, and we are already evaluating further growth opportunities for the business.

source:Röhm /echemi.com

Mitsui Chemicals, Hagihara Industries Jointly Develop Technology for Homogenizing Viscosity of Heterogeneous Recycled Plastics

Mitsui Chemicals, Inc and Hagihara Industries Inc. today announced that they have carried out joint development for technology to homogenize the viscosity of recycled plastics, resulting in the successful demonstration of this technology.

Background to the joint development 

Due to inconsistent quality among plastic waste, recycled plastics made using that waste can exhibit heterogeneous viscosity, leading to issues such as lower yields and an inability to use the recycled plastics outside of low-quality applications. In an effort to resolve these issues, Hagihara Industries and Mitsui Chemicals decided to take in-line viscosity measurement technology jointly developed by Mitsui Chemicals and the Nagaoka University of Technology and fit it to recycled pellet extruders to pursue the joint development of technology for homogenizing viscosity.

 

Mitsui Chemicals is aiming to achieve ongoing growth driven by solutions to social issues – and with this goal in mind, the company is working to make both society and the environment more sustainable via a transition to a circular economy. These efforts have previously seen Mitsui Chemicals work with the Nagaoka University of Technology on developing viscosity homogenization technology that leverages tandem extrusion to control viscosity in recycled plastic, with the aid of in-line viscometers capable of measuring plastic waste viscosity in real time.

 

Meanwhile, Japan’s largest manufacturer of blue tarps, Hagihara Industries is aiming to help bring about a sustainable society. As part of this pursuit, 2021 saw the company launch a Japan-first project called ReVALUE+™, which uses discarded blue tarps as a raw material to produce new blue tarps through horizontal recycling. However, the fact that discarded tarps are mixed with contaminants and other companies’ products upon recovery has caused issues with the quality of the recycled goods, requiring limits on the proportion of recycled material used in horizontally recycled products.

 

Hagihara Industries is therefore aiming to improve the quality of recycled materials, which would in turn allow it to further increase the proportion of these materials in its products. To achieve this, the company is leveraging its production technology for industrial machinery to develop advanced cleaning technology and equipment, as well as granulation equipment with highly effective contaminant removal (i.e. advanced filtration) and technology for refining and improving resin viscosity.

 

Now, #MitsuiChemicals and #HagiharaIndustries have further developed this technology to create a method wherein viscosity can be homogenized using only a single extruder. The companies hope that this will lead to the popularization of high-quality material recycling and, in turn, progress toward a circular economy.

source: Mitsui Chemicals

Today's KNOWLEDGE Share : okra and fenugreek extracts can remove microplastics from water

Today's KNOWLEDGE Share

Study shows okra and fenugreek extracts can remove microplastics from water

The substances behind the slimy strings from okra and the gel from fenugreek seeds could trap microplastics better than a commonly used synthetic polymer. Previously, researchers proposed using these sticky natural polymers to clean up water.

Now, they report in ACS Omega that okra and/or fenugreek extracts attracted and removed up to 90% of microplastics in ocean water, freshwater & groundwater.

Rajani Srinivasan and colleagues have been exploring nontoxic, plant-based approaches to attract and remove contaminants from water. In one set of lab experiments, they found that polymers from okra, fenugreek & tamarind stick to microplastics, clumping together,sinking for easy separation from water.

Also spoke about successful demonstrations of the plant extracts in freshwater and ocean water at ACS Spring 2022, a meeting of the American Chemical Society. In this next stage of the research, they have optimized the process for okra and fenugreek extracts in various types of water. 

To extract the sticky plant polymers, the team soaked sliced okra pods and blended fenugreek seeds in separate containers of water overnight. Then, researchers removed the dissolved extracts from each solution & dried them into powders. Analyses showed that the powdered extracts contained polysaccharides, which are natural polymers. Initial tests in pure water spiked with microplastics showed that:

One gram of either powder in a quart (1 liter) of water trapped microplastics the most effectively. 

Dried okra and fenugreek extracts removed 67% and 93%, respectively, of the plastic in an hour. 

A mixture of equal parts okra & fenugreek powder reached maximum removal efficiency (70%) within 30 minutes. 

The natural polymers performed significantly better than the synthetic, commercially available polyacrylamide polymer used in wastewater treatment.  

Okra works best in ocean water whereas fenugreek in groundwater

Then the researchers tested the plant extracts on real microplastic-polluted water. They collected samples from waterbodies around Texas and brought them to the lab. The plant extract removal efficiency changed depending on the original water source: Okra worked best in ocean water (80%), fenugreek in groundwater (80-90%), and the 1:1 combination of okra & fenugreek in freshwater (77%). The researchers hypothesize that the natural polymers had different efficiencies because each water sample had different types, sizes and shapes of microplastics.

Polyacrylamide is currently used to remove contaminants during wastewater treatment, but the researchers say that okra and fenugreek extracts could serve as biodegradable & nontoxic alternatives.  

Utilizing these plant-based extracts in water treatment will remove microplastics & other pollutants without introducing additional toxic substances to the treated water.

Source: American Chemical Society/omnexus.specialchem.com

Avecom partners with Green Alchemy to turn waste streams into bio-based products

Avecom, a provider of solutions in environmental remediation and biomass fermentation, has partnered with Green Alchemy ApS, a consultancy dedicated to turning complex regulatory and policy challenges into opportunities. Together, they aim to help companies valorize industrial waste streams for food and feed, bio-based materials, agriculture, and other sectors.

Transition opportunity to circular economy:

This partnership creates a one-stop shop, offering technical, economic, and regulatory feasibility assessments to companies that seek to valorize their waste streams.

The current global economic model is largely based on a linear resource flow, which is unsustainable in the long term. A shift to a circular economy presents a viable solution, and the EU has been increasingly prioritizing efforts in this direction to enhance strategic autonomy and competitiveness.

Bio-based solutions and biomanufacturing are key to the transition, as they enable converting agricultural and industrial waste streams into valuable products like proteins, #biopolymers, and organic fertilizers. Companies that successfully implement these solutions reduce waste and related costs, improve resource efficiency, and create new revenue streams.

Valorization assessment

Tapping into the opportunity requires know-how and infrastructure to develop and scale bio-based solutions. Avecom specializes in this domain by using biomass fermentation.

"We bring to the table 30 years of experience in microbial resource management, a skilled team of technical and engineering experts, and fully equipped labs and pilot or scale-up facilities. With our support, our customers are able to convert an otherwise lost flow into a new product, bringing additional profit to their businesses”, said Stijn Boeren, director of Avecom.

"But the first step in turning waste into a value is the waste-stream valorization assessment. At #Avecom, we conduct technical and economic feasibility studies to help our customers identify the most profitable options for their waste streams”.

While mapping out the technical and economic potential is crucial, the resulting different scenarios must also be evaluated from a regulatory standpoint. This is where Green Alchemy's expertise plays a vital role.

At #GreenAlchemy, we guide companies through complex policies and compliance requirements and make sure that regulatory considerations are addressed from the start. This is how we help our customers make informed investment decisions and avoid costly missteps”, said Claudia Herrmann, co-founder of Green Alchemy ApS. "Our focus is on the bio-based solutions, and we are working with startups and investors in the sector to bring these innovations to the market”.

source: Avecom /polymer-additives.specialchem.com