The power of 3D printing lies in the materials used and no one knows this better than Oak Ridge National Laboratory (ORNL), which is currently researching both carbon fiber and metal 3D printing technologies.
Now ORNL can lignin to its repertoire of material expertise.
In the journal Applied Materials Today, ORNL researchers outline their patent-pending process for developing 3D printable lignin, an organic polymer found in the walls of plant cells as well as a common byproduct in the production of biofuels. The study’s authors explain that, given the unrenewable and polluting nature of ubiquitous petroleum-based plastics, it’s necessary to find a sustainable replacement based on renewable sources, such as lignin, which provides plans and some algae with their structure.
Lignin-based composites are often difficult to process, making it possible only to produce objects using compression molding or casting. Therefore, ORNL sought to find a new method for processing the material in such a way that would yield more practical and scalable applications. For this reason, the team turned to fused deposition modeling (FDM) 3D printing.
To create a 3D printable lignin composite, ORNL combined Organosolv hardwood lignin with several different materials, including acrylonitrile-butadiene rubber (NBR41), acrylonitrile-butadiene-styrene (ABS) and carbon fiber. The composites were then formed into 3D printer filament and printed using a LulzBot TAZ 3D printer.
A micrograph showing a cross-section of the weld area between two 3D-printed layers of the lignin-based composite material. (Image courtesy of Christopher Bowland/Oak Ridge National Laboratory, U.S. Dept. of Energy.)
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