Processing Bulk Natural Wood into a High-Performance Structural Material
As a readily available and affordable resource, wood has been widely used to build homes and construct furniture. Its applications could expand if enhanced mechanical properties such as strength, impact resistance or longer water resistance could be achieved. Such a goal is being reached throughout a process combining chemical treatment followed by mechanical compression.
Wood is first boiled in a solution of NaOH/Na2SO3 to make it more porous and less rigid. The treatment removes nearly 75% of hemicellulose and 50% of lignin. Wood is then compressed perpendicularly to its growth direction at 100°C. The monolayers of such densified wood can be assembled at 90° rotation in the form of laminate that contains several layers. The resulting assemblage has a specific strength much higher than that of most metals and alloys