Researchers have found a way to make wood so strong that it could replace steel in any application, including in cars and airplanes.
The researchers believe that the new process, detailed in the journal Nature, could make wood stronger than even many titanium alloys.
“This new way to treat wood makes it 12 times stronger than natural wood and 10 times tougher,” said lead researcher Liangbing Hu, Associate Professor at University of Maryland in the US.
“This kind of wood could be used in cars, airplanes, buildings — any application where steel is used,” Hu said.
The new wood treatment process involves two steps. The first step involves partial removal of lignin — the glue between wood cells — and hemicellulose (which increases the packing density of the cell wall) from the natural wood via a boiling process in an aqueous mixture of sodium hydroxide and sodium sulphite.
This is followed by hot-pressing, leading to the total collapse of cell walls and the complete densification of the natural wood with highly aligned cellulose nanofibres.
“This strategy is shown to be universally effective for various species of wood,” the study said.
The team measured the dense wood’s mechanical properties and found it to be both strong and tough.
“It is 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 moulded at the beginning of the process,” said Teng Li, Associate Professor at University of Maryland.
The team also tested the new wood material and natural wood by shooting bullet-like projectiles at it.
The projectile blew straight through the natural wood. The fully treated wood stopped the projectile partway through, the study said.
“Soft woods like pine or balsa, which grow fast and are more environmentally friendly, could replace slower-growing but denser woods like teak in furniture or buildings,” Hu said.