Wood is sharper than steel? In this case, well yes…
Scientists have discovered a new hardened form of natural material that can be converted into sharp knives and sturdy nails as an alternative of wood processing. The knife which is made from wood is nearly three times sharper than your average dinner table knife and can even be washed in a dishwasher without causing any damages.
This new hard form of wood is the brainchild of scientists at the University of Maryland who supercharged the material’s natural strength which lies in the cellulose packed inside. Cellulose is the primary component of wood which comprises 40-50% of the material and has a higher strength-to-density ratio than ceramics, metals, polymers and other engineered materials.
So how come wood isn’t as strong as the rest of them? Turns out, the remaining material present in wood is made up of hemicellulose and lignin which dilutes the overall strength of the cellulose and hinders its applications. The authors of the study decided to remove these weaker parts of the wood while preserving the cellulose structures to make it stronger than the average wood structure.
“It’s a two-step process,” says senior author Teng Li. “In the first step, we partially delignify wood. Typically, wood is very rigid, but after removal of the lignin, it becomes soft, flexible, and somewhat squishy. In the second step, we do a hot press by applying pressure and heat to the chemically processed wood to densify and remove the water.”
The hardened wood was then carved into a knife and coated with mineral oil to prevent cellulose from absorbing water and help extend the knife’s sharpness and make it dishwasher safe. The resultant knife is 3 times sharper than a stainless steel knife and 23 times harder than natural wood. For your point of reference, it can easily cut through a medium-well done steak without any problem.
The scientists hope this new form of wood can come to offer an eco-friendly alternative to steel and ceramics and help reduce environmental pollution which comes from burning of the materials at high temperatures.