Superdense wood is lightweight, but strong as steel
Boiled and crushed lumber could be used to build everything from bridges to cars
TOUGH STUFF A new wood-compacting process crushes the gaps between cell walls in natural wood (porous structure seen in the scanning electron microscopy image, left), making the densified wood (right) as strong as steel.
J. Song et al/Nature 2018
Newly fabricated superstrong lumber gives a whole new meaning to “hardwood.”
This ultracompact wood, described in the Feb. 8 Nature, is created by boiling a wood block in a water-based solution of sodium hydroxide and sodium sulfite. The chemicals partially strip the wood of substances called lignin and hemicellulose, which help give wood its structure and rigidity. Then the block gets squeezed between metal plates heated to 100° Celsius at a pressure of 5 megapascals — about 50 times the pressure of sea-level atmosphere. That squashes the gaps between the cell walls in the wood, shrinking the block to about 20 percent its original thickness and making it three times denser.
Researchers found that the densified wood could withstand being stretched or pulled 11.5 times harder than its natural counterpart
