Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

3D printer inks from the woods

30.05.2017

Empa 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.

In order to produce 3D microstructured materials for automobile components, for instance, Empa researchers have been using a 3D printing method called “Direct Ink Writing” for the past year (DIW, see box). 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.


Rod-like cellulose nanocrystals (CNC) approximately 120 nanometers long and 6.5 nanometers in diameter under the microscope. (Image: Empa)

Empa researchers Gilberto Siqueira and Tanja Zimmermann from the Laboratory for Applied Wood Materials have now succeeded, together with colleagues from Harvard University and ETH Zürich, in developing a new, environmentally friendly 3D printing ink made from cellulose nanocrystals (CNC).

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. "The places with a higher degree of order appear in a more crystalline form.

... more about:
»3D printer »Cellulose »Empa »Nanocrystals »woods

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. Previous inks contained a rather small proportion of “biological” materials, with a maximum of 2.5 percent CNC. The Empa team wished to increase this proportion, as they have now succeeded in doing – 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.

The first CNC mixtures were water-based. This did work in principle, but yielded a very brittle material. Therefore, Siqueira and his colleagues developed a second, polymer-based recipe that had a decisive advantage: after printing and hardening using UV radiation, the CNC “cross-linked” with polymer building blocks, which gave the composite material a significantly higher degree of mechanical rigidity.

Bringing things together despite resistance

What sounds quite simple in retrospect caused the Empa team a great deal of head-scratching. Siqueira: "Most polymers are water-repellent or hydrophobic, whereas cellulose attracts water – it is hydrophilic. As a result they are not very compatible." So the researchers first of all had to chemically modify the CNC surface.

After the first attempts at printing and X-ray analysis of the obtained microstructures, the researchers noticed that the CNC in the printed object had aligned itself almost perfectly in the direction it was printed in. They concluded that the mechanical strength used to push the ink through the printing nozzle was sufficient to align it. "It is pretty interesting that one can so easily control the direction of the nanocrystals, for example, if you want to print something that should have a specific mechanical rigidity in a certain direction", says Siqueira.

Lots and lots of possibilities

These outstanding mechanical properties represent a decisive advantage compared to other materials such as carbon fibers, which are also used in DIW inks. In addition, the new kind of ink from the Empa lab is made from a renewable material – cellulose.

"Cellulose is the most frequently occurring natural polymer on Earth", says Siqueira. It is not just found in trees, but also in other plants and even in bacteria. The crystals, which are isolated from various cellulose sources, are morphologically different from each other and differ in size, but not in their properties. And they may also be of interest to, for example, the automobile industry or for packaging of any kind.

"However, the most important area of application for me is in biomedicine", says Siqueira, "for example in implants or prostheses". The Empa researcher is convinced that the CNC material is suitable for a wide variety of different applications due to its outstanding mechanical properties, as well as the possibility of chemical modification and alignment during printing.

These possibilities are currently being investigated further at Empa. A PhD student is currently focusing on the further development of the materials and the printing method for other applications. In addition, a Master’s student intends to develop other “biological” inks. "Research in this field is only just beginning", says Gilberto Siqueira. "Printing with biopolymers is currently a very hot topic."

Weitere Informationen:

http://www.empa.ch/web/s604/cellulose-ink

Cornelia Zogg | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

Further reports about: 3D printer Cellulose Empa Nanocrystals woods

More articles from Life Sciences:

nachricht New catalyst controls activation of a carbon-hydrogen bond
21.11.2017 | Emory Health Sciences

nachricht The main switch
21.11.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Previous evidence of water on mars now identified as grainflows

21.11.2017 | Physics and Astronomy

NASA's James Webb Space Telescope completes final cryogenic testing

21.11.2017 | Physics and Astronomy

New catalyst controls activation of a carbon-hydrogen bond

21.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>