During the development, sheets of the new densified wood material were subjected to ballistic testing and partially resisted total projectile penetration, said the engineers.

The two-step process involves the partial removal of lignin and hemicellulose from the natural wood via a boiling process in an aqueous mixture of sodium hydroxide (NaOH) and sodium sulphite (Na2SO3) 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,” said the researchers. “Our processed wood has a specific strength higher than that of most structural metals and alloys, making it a low-cost, high-performance, lightweight alternative.”