Scientists from the University of Maryland may have discovered a more eco-friendly alternative to ceramics and stainless steel for our knives and nails by figuring out how to chemically alter wood so that it can be fashioned into strong nails or knives that are three times sharper than a standard dinner table knife.
The team at the University of Maryland sought to supercharge the material’s natural strength, which comes from the cellulose packed inside the wood. Cellulose, which accounts for 40 to 50 percent of the material, is the primary component of wood and has a higher strength-to-density ratio than plenty of engineered materials like ceramics, metals, and polymers.
That said, the remainder of the wood is comprised of the binding materials hemicellulose and lignin, which tempers its strength. To address this, the scientists found out how to remove these weaker parts of the wood while preserving the cellulose structures.
“It’s a two-step process,” senior author Teng Li explains. “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.”
Then, the hardened wood material is carved into a knife and coated in mineral oil, which cancels out the natural tendency of cellulose to absorb water. This makes the material more durable and dishwasher safe. The knife made of hardened wood is almost three times sharper than a stainless steel dinner table knife and is 23 times harder than natural wood.
The team also fashioned nails out of the hardened wood, which were just as sharp as regular steel nails with the added benefit of being rust-resistant.
The scientists hope that this chemically treated wood will be used to replace plastic, and steel, and ceramics, which have to be forged in furnaces at extreme temperatures, releasing CO2 into the atmosphere.