Cellulose-based Ink For 3D Printing

Empa (Switzerland) researchers have succeeded in developing an environmentally friendly ink for 3D printing based on cellulose nanocrystals. This technology can be used to fabricate microstructures with outstanding mechanical properties, which have promising potential uses in implants and other biomedical applications.

Cellulose, along with lignin and hemicellulose, is one of the main constituents of wood. The biopolymer consists of glucose chains organized in long fibrous structures. In some places the cellulose fibrils exhibit a more ordered structure.

In order to produce 3D microstructured materials for composite applications, for instance, Empa researchers have been using a 3D printing method called “Direct Ink Writing” for the past year. During this process, a viscous substance – the printing ink – is squeezed out of the printing nozzles and deposited onto a surface, pretty much like a pasta machine. Empa researchers Gilberto Siqueira and Tanja Zimmermann from the Laboratory for Applied Wood Materials have now succeeded, together with Jennifer Lewis from Harvard University and André Studart from the ETH Zürich, in developing a new, environmentally friendly 3D printing ink made from cellulose nanocrystals (CNC).
The places with a higher degree of order appear in a more crystalline form. And it is these sections, which we can purify with acid, that we require for our research“, explains Siqueira. The final product is cellulose nanocrystals, tiny rod-like structures that are 120 nanometers long and have a diameter of 6.5 nanometers. And it is these nanocrystals that researchers wanted to use to create a new type of environmentally friendly 3D printing ink.They have now succeeded that  their new inks contain a full 20 percent CNC.

The biggest challenge was in attaining a viscous elastic consistency that could also be squeezed through the 3D printer nozzles“, says Siqueira. The ink must be “thick” enough so that the printed material stays “in shape” before drying or hardening, and doesn’t immediately melt out of shape again.

Source: https://www.empa.ch/

Wood Mixed With Nanoparticles Filters Toxic Water

Engineers at the University of Maryland have developed a new use for wood: to filter water. Liangbing Hu of the Energy Research Center and his colleagues added nanoparticles to wood, then used it to filter toxic dyes from water.

The team started with a block of linden wood, which they then soaked in palladium – a metal used in cars’ catalytic converters to remove pollutants from the exhaust. In this new filter, the palladium bonds to particles of dye. The wood’s natural channels, that once moved water and nutrients between the leaves and roots, now allow the water to flow past the nanoparticles for efficient removal of the toxic dye particles. The water, tinted with methylene blue, slowly drips through the wood and comes out clear.

VIDEO: Wood filter removes toxic dye from water

This could be used in areas where wastewater contains toxic dye particles,” said Amy Gong, a materials science graduate student, and co-first author of the research paper.

The purpose of the study was to analyze wood via an engineering lens. The researchers did not compare the filter to other types of filters; rather, they wanted to prove that wood can be used to remove impurities.

We are currently working on using a wood filter to remove heavy metals, such as lead and copper, from water,’ said Liangbing Hu, the lead researcher on the project. “We are also interested in scaling up the technology for real industry applications.” Hu is a professor of materials science and a member of the University of Maryland’s Energy Research Center.

Source: http://www.mse.umd.edu/

Wooden SkyScrapers

High-rise wooden buildings, such as 14-storey apartment building “The Tree” in Norway, are altering city skylines in what the timber industry is heralding as a new era that will dent the supremacy of concrete and steel.

wooden skyscraper

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Situated on the Bergen waterfront, The Tree is the tallest wooden building in the world. The 52.8 metre high structure is one of a growing number of so-called Plyscrapers altering city skylines. The timber industry say it’s an environmental solution, as countries seek to reduce emissions.

It will never totally displace concrete and steel, but it’s definitely a part in our solution towards our struggle towards a CO2 neutral society,”  says Ole Herman Kleppe, Chief Project Manager.

The architects insist that fears of fire in such timber homes are groundless.  “These columns and these CLT panels they don’t burn. They’re so thick that they don’t burn. In addition, they are painted with fire resistant paint and the house is sprinkled so we have all possible ways to prevent a fire in the house. So actually, this is the safest house in Bergen regarding fire.” explains Kleppe.

The 14-storey structure is made of sustainable wood. But concrete makers dispute the idea that timber is greener, insisting that deforestation causes more CO2 emissions. The Tree’s structure isn’t entirely wooden.

It’s concrete on this roof because it adds weight and it was necessary to add weight to this wooden building because it kind of dampens the swinging,” adds Per Reigstad, architect at Artec.

Later this year a wooden building that’s two inches taller will open in Vancouver. Even taller structures are being planned in Vienna and London.

Source: http://www.reuters.com/

Transparent Wood Brightens Homes

When it comes to indoor lighting, nothing beats the sun’s rays streaming in through windows. Soon, that natural light could be shining through walls, too. Scientists from the KTH Royal Institute of Technology (Sweden) have developed transparent wood that could be used in building materials and could help home and building owners save money on their artificial lighting costs. Their material, reported in ACS’ journal Biomacromolecules, also could find application in solar cell windows.

transparent wood

Homeowners often search for ways to brighten up their living space. They opt for light-colored paints, mirrors and lots of lamps and ceiling lights. But if the walls themselves were transparent, this would reduce the need for artificial lighting — and the associated energy costs. Recent work on making transparent paper from wood has led to the potential for making similar but stronger materials. Lars Berglund and colleagues from KTH the wanted to pursue this possibility.

The researchers removed lignin from samples of commercial balsa wood. Lignin is a structural polymer in plants that blocks 80 to 95 percent of light from passing through. But the resulting material was still not transparent due to light scattering within it. To allow light to pass through the wood more directly, the researchers incorporated acrylic, often known as Plexiglass. The researchers could see through the resulting material, which was twice as strong as Plexiglass. Although the wood isn’t as crystal clear as glass, its haziness provides a possible advantage for solar cells. Specifically, because the material still traps some light, it could be used to boost the efficiency of these cells, the scientists note.

Source: http://www.acs.org/
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https://www.kth.se/

Wood Added With Carbon Nanotubes Printed In 3D

Paul Gatenholm, professor in Polymer TA group of researchers at Chalmers University of Technology (Sweden)  have managed to print and dry three-dimensional objects made entirely by cellulose for the first time with the help of a 3D-bioprinter. They also added carbon nanotubes to create electrically conductive material. The effect is that cellulose and other raw material based on wood will be able to compete with fossil-based plastics and metals in the on-going additive manufacturing revolution, which started with the introduction of the 3D-printer.

3D printing is a form of additive manufacturing that is predicted to revolutionise the manufacturing industry. The precision of the technology makes it possible to manufacture a whole new range of objects and it presents several advantages compared to older production techniques. The freedom of design is great, the lead time is short, and no material goes to wastePlastics and metals dominate additive manufacturing. However, a research group at Chalmers University of Technology have now managed to use cellulose from wood in a 3D printer.

wood computer chipCombing the use of cellulose to the fast technological development of 3D printing offers great environmental advantages,” says Paul Gatenholm, professor of Biopolymer Technology at Chalmers and the leader of the research group. “Cellulose is an unlimited renewable commodity that is completely biodegradable, and manufacture using raw material from wood, in essence, means to bind carbon dioxide that would otherwise end up in the atmosphere.”

The breakthrough was accomplished at Wallenberg Wood Science Center, a research center aimed at developing new materials from wood, at Chalmers University of Technology.

 

Source: http://www.chalmers.se/

Nanotechnology Declares War Against Termites

Scientists at the University of Queensland, Australia, have found that mesoporous silica nanoparticles are able to store and deliver biocides in a controlled manner over time. The discovery could help the timber industry control termites. Termites cause  tens of billions dollars  in damage each year around the world, and are considered to be a significant threat to the timber industry throughout the tropics and subtropics. Conventional methods of eradicating the pests use agrochemical biocides that cause environmental damage via bioaccumulation.

The new method uses the pore structure of the mesoporous silica nanoparticles to adsorb biocides, which are then released in a controlled manner. The slow release means the termites will feed on and transfer the substance to other termites, resulting in eventual colony destruction. The team, said Zhang Qiao, who is heading up the research, is investigating how to further control the release of the biocide, saying the nanoparticles need to be coated with other chemicals in order to effectively deliver their cargo. They are investigating a biodegradable polymer coating.