Scientists at the Department of Energy's Oak Ridge National Laboratory have created a recipe for a renewable 3D printing feedstock that could spur a profitable new use for an intractable biorefinery byproduct: lignin.
The discovery, detailed in Science Advances, expands ORNL's achievements in lowering the cost of bioproducts by creating novel uses for lignin--the material left over from the processing of biomass.
Using as much as 50 percent lignin by weight, a new composite material created at ORNL is well suited for use in 3D printing.
Credit: Oak Ridge National Laboratory
Lignin gives plants rigidity and also makes biomass resistant to being broken down into useful products.
"Finding new uses for lignin can improve the economics of the entire biorefining process," said ORNL project lead Amit Naskar.
Researchers combined a melt-stable hardwood lignin with conventional plastic, a low-melting nylon, and carbon fiber to create a composite with just the right characteristics for extrusion and weld strength between layers during the printing process, as well as excellent mechanical properties.
The work is tricky. Lignin chars easily; unlike workhorse composites like acrylonitrile-butadiene-styrene (ABS) that are made of petroleum-based thermoplastics, lignin can only be heated to a certain temperature for softening and extrusion from a 3D-printing nozzle. Prolonged exposure to heat dramatically increases its viscosity--it becomes too thick to be extruded easily.
But when researchers combined lignin with nylon, they found a surprising result: the composite's room temperature stiffness increased while its melt viscosity decreased. The lignin-nylon material had tensile strength similar to nylon alone and lower viscosity, in fact, than conventional ABS or high impact polystyrene.
The scientists conducted neutron scattering at the High Flux Isotope Reactor and used advanced microscopy at the Center for Nanophase Materials Science--both DOE Office of Science User Facilities at ORNL--to explore the composite's molecular structure.
They found that the combination of lignin and nylon "appeared to have almost a lubrication or plasticizing effect on the composite," noted Naskar.
"Structural characteristics of lignin are critical to enhance 3D printability of the materials," said ORNL's Ngoc Nguyen who collaborated on the project.
Scientists were also able to mix in a higher percentage of lignin--40 to 50 percent by weight--a new achievement in the quest for a lignin-based printing material. ORNL scientists then added 4 to 16 percent carbon fiber into the mix. The new composite heats up more easily, flows faster for speedier printing, and results in a stronger product.
"ORNL's world-class capabilities in materials characterization and synthesis are essential to the challenge of transforming byproducts like lignin into coproducts, generating potential new revenue streams for industry and creating novel renewable composites for advanced manufacturing," said Moe Khaleel, associate laboratory director for Energy and Environmental Sciences.
The lignin-nylon composite is patent-pending and work is ongoing to refine the material and find other ways to process it. The ORNL research team also included Sietske Barnes, Christopher Bowland, Kelly Meek, Kenneth Littrell and Jong Keum. The research was funded by DOE's Office of Energy Efficiency and Renewable Energy's Bioenergy Technologies Office.
ORNL is managed by UT-Battelle for the Department of Energy's Office of Science, the single largest supporter of basic research in the physical sciences in the United States. DOE's Office of Science is working to address some of the most pressing challenges of our time. For more information, please visit https:/
Kim Askey | EurekAlert!
Crystal with a twist: Scientists grow spiraling new material
21.06.2019 | University of California - Berkeley
A new manufacturing process for aluminum alloys
19.06.2019 | DOE/Pacific Northwest National Laboratory
From June 25th to 27th 2019, the Fraunhofer Institute for Digital Media Technology IDMT in Ilmenau (Germany) will be presenting a new solution for acoustic quality inspection allowing contact-free, non-destructive testing of manufactured parts and components. The method which has reached Technology Readiness Level 6 already, is currently being successfully tested in practical use together with a number of industrial partners.
Reducing machine downtime, manufacturing defects, and excessive scrap
The quality of additively manufactured components depends not only on the manufacturing process, but also on the inline process control. The process control ensures a reliable coating process because it detects deviations from the target geometry immediately. At LASER World of PHOTONICS 2019, the Fraunhofer Institute for Laser Technology ILT will be demonstrating how well bi-directional sensor technology can already be used for Laser Material Deposition (LMD) in combination with commercial optics at booth A2.431.
Fraunhofer ILT has been developing optical sensor technology specifically for production measurement technology for around 10 years. In particular, its »bd-1«...
The well-known representation of chemical elements is just one example of how objects can be arranged and classified
The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...
Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.
Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...
Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.
The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...
24.06.2019 | Event News
29.04.2019 | Event News
17.04.2019 | Event News
25.06.2019 | Architecture and Construction
25.06.2019 | Life Sciences
25.06.2019 | Power and Electrical Engineering