From DOE’s Oak Ridge National Laboratory (US) via COSMOS (AU) : “Sandy-dandy invention shows its strength”

From DOE’s Oak Ridge National Laboratory (US)

via

Cosmos Magazine bloc

COSMOS (AU)

16 November 2021
Deborah Devis

Superstrong sand structure could be used in aeronautics.

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A novel polymer developed at Oak Ridge National Laboratory strengthens sand for additive manufacturing applications. A 6.5 centimeter 3D-printed sand bridge, shown here, held 300 times its own weight. Credit: Dustin Gilmer/ The University of Tennessee-Knoxville (US).

Building sandcastles just got a whole new meaning, thanks to a manufacturing invention that has a sand-based polymer holding up to 300 times its own weight.

Researchers at the Oak Ridge National Laboratory, US, designed a novel polymer that binds to silica sand. It can be 3D printed into integrated geometries that massively increase the sand’s strength, but it is also water-soluble for getting rid of in a hurry.

In the study, published in Nature Communications, the team 3D printed a 6.5-centimeter bridge that can hold 300 times its own weight – that’s like 12 Empire State Buildings sitting on the Brooklyn Bridge!

The printer uses a liquid polymer-polyethyleneimine (PEI)-to bind to powdered sand building the structure layer by layer. This doubled the strength of the sand compared to other polymer binders.

When removed from the printer, the structure was porous and had lots of holes, which were filled with a glue called cyanoacrylate. This second step increased the strength a further eight times, making it stronger than any known building material, including masonry.

“Few polymers are suited to serve as a binder for this application,” says lead researcher Tomonori Saito of Oak Ridge National Laboratory.

“We were looking for specific properties, such as solubility, that would give us the best result. Our key finding was in the unique molecular structure of our PEI binder that makes it reactive with cyanoacrylate to achieve exceptional strength.”

This new material could be used to create composite parts in the likes of the automotive and aerospace sectors – lightweight materials such as carbon fibre and fibreglass could be wrapped around 3D-printed sand cores, often called tools, and cured with heat.

The silica sand is particularly useful for this tooling because it doesn’t change shape with heat and can be later “washed out” when the wrapped material is cured, because the polymer is water-soluble.

“To ensure accuracy in tooling parts, you need a material that does not change shape during the process, which is why silica sand has been promising,” says lead author Dustin Gilmer of the University of Tennessee in the US. “The challenge has been to overcome structural weakness in sand parts.”

Previous sand-based tools easily broke apart under heat pressure, so had limited industrial use.

“Our high-strength polymer-sand composite elevates the complexity of parts that can be made with binder-jetting methods, enabling more intricate geometries, and widens applications for manufacturing, tooling and construction,” says Gilmer.

See the full article here .

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Established in 1942, DOE’s Oak Ridge National Laboratory (US) is the largest science and energy national laboratory in the Department of Energy system (by size) and third largest by annual budget. It is located in the Roane County section of Oak Ridge, Tennessee. Its scientific programs focus on materials, neutron science, energy, high-performance computing, systems biology and national security, sometimes in partnership with the state of Tennessee, universities and other industries.

ORNL has several of the world’s top supercomputers, including Summit, ranked by the TOP500 as Earth’s second-most powerful.

ORNL OLCF IBM AC922 SUMMIT supercomputer, was No.1 on the TOP500..

The lab is a leading neutron and nuclear power research facility that includes the Spallation Neutron Source and High Flux Isotope Reactor.

It hosts the Center for Nanophase Materials Sciences, the BioEnergy Science Center, and the Consortium for Advanced Simulation of Light Water Nuclear Reactors.

ORNL is managed by UT-Battelle for the Department of Energy’s Office of Science. DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time.

Areas of research

ORNL conducts research and development activities that span a wide range of scientific disciplines. Many research areas have a significant overlap with each other; researchers often work in two or more of the fields listed here. The laboratory’s major research areas are described briefly below.

Chemical sciences – ORNL conducts both fundamental and applied research in a number of areas, including catalysis, surface science and interfacial chemistry; molecular transformations and fuel chemistry; heavy element chemistry and radioactive materials characterization; aqueous solution chemistry and geochemistry; mass spectrometry and laser spectroscopy; separations chemistry; materials chemistry including synthesis and characterization of polymers and other soft materials; chemical biosciences; and neutron science.
Electron microscopy – ORNL’s electron microscopy program investigates key issues in condensed matter, materials, chemical and nanosciences.
Nuclear medicine – The laboratory’s nuclear medicine research is focused on the development of improved reactor production and processing methods to provide medical radioisotopes, the development of new radionuclide generator systems, the design and evaluation of new radiopharmaceuticals for applications in nuclear medicine and oncology.
Physics – Physics research at ORNL is focused primarily on studies of the fundamental properties of matter at the atomic, nuclear, and subnuclear levels and the development of experimental devices in support of these studies.
Population – ORNL provides federal, state and international organizations with a gridded population database, called Landscan, for estimating ambient population. LandScan is a raster image, or grid, of population counts, which provides human population estimates every 30 x 30 arc seconds, which translates roughly to population estimates for 1 kilometer square windows or grid cells at the equator, with cell width decreasing at higher latitudes. Though many population datasets exist, LandScan is the best spatial population dataset, which also covers the globe. Updated annually (although data releases are generally one year behind the current year) offers continuous, updated values of population, based on the most recent information. Landscan data are accessible through GIS applications and a USAID public domain application called Population Explorer.