A University of Maryland (UMD) research team developed a technique for creating strong and moldable wood materials via a rapid "water-shock" process.
The team, led by Liangbing Hu, materials science and engineering professor and director of the Center for Materials Innovation at the University of Maryland, dismantled the wood’s lignin – the cell walls inside wood that give it strength – which softens it, an then closed the fibers via evaporation. The team then re-swelled the wood by "shocking" it with water.
"The rapid water-shock process forms a distinct partially open, wrinkled cell wall structure that provides space for compression as well as the ability to support high strain, allowing the material to be easily folded and molded," Hu said. "The resulting 3D-Molded Wood is six-times stronger than the starting wood and comparable to widely used lightweight materials like aluminum alloys."
This ‘moldable wood’ can then be folded into different shapes and then set to dry before forming the final product. The remarkable foldability of the processed wood originates in its wrinkled cell wall structure, which can sustain severe folding without fracture.
"Moldable wood significantly broadens the potential applications of wood as a sustainable structural material, while reducing the environmental impact for buildings and transportation applications" said Teng Li, mechanical engineering professor at UMD and co-author on the study on the technique, which appeared in the Oct. 21 edition of Science magazine.
In addition to UMD researchers, scientists from Yale University, Ohio State University, USDA Forest Service, University of Bristol, University of North Texas, ETH Zurich, and the Center for Materials Innovation collaborated on the study..
Indeed, "this out-of-the-box approach to developing advanced wood materials will drive wood product and market innovation as a sustainable solution to replace many unsustainable structure materials and combat climate change," said JY Zhu at the USDA Forest Products Lab. "It will also facilitate mitigating forest thinning cost for healthy forest management to reduce wild catastrophic forest fires. We at the U.S. Forest Service Forest Products Laboratory are very excited to collaborate with Professor Hu on this research."
"The researchers introduce a clever means to transform the naturally occurring, straight-walled cellular structures of wood into wavy, accordion-like geometries, at the microscale," said John Rogers, professor of materials science and engineering, biomedical engineering and neurological surgery at Northwestern University. "The result is an unusual, high-strength form of wood that is both flexible and moldable, in ways that open up new applications for this very old class of material."
Dr. Hu founded InventWood LLC in 2016 to commercialize the advanced wood technologies invented at his lab, including this 3D moldable wood. For additional details, visit: www.inventwood.com.
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