Scientists at University of Maryland in the United States have developed a new technique that makes wood as strong as steel or even titanium alloys.
This ‘Super Wood’ can have potential applications in construction, automobiles, and aviation industries.
“This new way to treat wood makes it 12 times stronger than natural wood and 10 times tougher,” said associate professor Liangbing Hu, who led the team of researchers.
A statement issued by University of Maryland’s A. James Clark School of Engineering said that the technique entailed removal of wood’s lignin, the part of the wood that makes it rigid and gives it brown color. “It is compressed at temperatures of 150 degrees Fahrenheit. This causes the cellulose fibers to become very tightly packed, which makes the wood five times thinner than its original size. Any defects like holes or knots are crushed together. The treatment process was extended a little further with a coat of paint. The wood’s fibers are pressed together so tightly that they can form strong hydrogen bonds, like a crowd of people who can’t budge — who are also holding hands.”
On testing the dense wood’s mechanical properties, the team found it as strong as steel, but six times lighter. “It takes 10 times more energy to fracture than natural wood. It can even be bent and molded at the beginning of the process,” Professor Teng Li, who co-led the study, was quoted as saying in the school’s statement.
The team also tested the material by shooting a bullet-like projectile at it. Unlike natural wood, which was blown straight through, the fully treated wood stopped the projectile partway through.
Commenting on the study, Huajian Gao, a professor at Brown University, said, “The paper provides a highly promising route to the design of light weight, high performance structural materials, with tremendous potential for a broad range of applications where high strength, large toughness, and superior ballistic resistance are desired. The method can be used with various species of wood and is fairly easy to implement.”
He said that the wood developed with the new technique could be used in any application where steel is used.
Another expert, Dr. Zhigang Suo, a professor of mechanics and materials at Harvard University, said that the two-step process adopted by the research team had managed to achieve exceptionally high strength, much beyond what was reported in the literature. “Given the abundance of wood, as well as other cellulose-rich plants, this paper inspires imagination,” he noted.