Hardened wood knife boasts three times the sharpness of stainless steel

Scientists have developed a hardened wood material that, when sharpened, is three times sharper than a stainless steel dinner knife, according to the new study on the work. The research comes from the University of Maryland's Teng Li and a team that developed a new method to generate extremely hard wood. Among other things, the development may lead to more sustainable building materials.

Wood contains between 40- and 50-percent cellulose, with the rest of the material compromised of binders called lignin and hemicellulose. While cellulose has a greater strength-to-density ratio than materials like metal and ceramic, the binder materials make wood overall weaker than man-made counterparts.

The new study involved stripping away those weaker binding materials while leaving the cellulose untouched. This process involves first removing the lignin, which results in what the researchers say is a squishy, soft material. That lignin-free wood is then subjected to heat and pressure via a hot press to remove the water and increase the density. A simple coating of mineral oil is then applied to boost the wood's lifespan.

The result is an incredibly hard wood that can be used for things like dishwasher-safe knives and even nails that can be pounded through boards without damage. In addition to offering a potentially more sustainable, environmentally-friendly alternative to man-made materials like stainless steel, there are also benefits like a lack of rusting concerns that may, for example, reduce the longevity of an outdoor building made with metal nails.

The researchers say additional research on the hardened wood product is needed to confirm whether this processing method reduces environmental impact compared to man-made materials. However, the material does hold promise for more durable wood-based items going forward, including hardwood floors that hold up better against wear and tear and everyday items like more durable cutting boards.