Wood has been used for millennia for building and has some great technical properties. It has, however, some drawbacks that have barred it from certain applications until now. Its most notable shortcoming is strength, and engineers typically lean more heavily on metal when rigidity and toughness are the top priority. Scientists at the University of Maryland, College Park have found a simple way to make wood super-dense and incredibly strong, the work was just published in Nature.
In order to produce this super wood, the team first boiled the wood in a mixture of sodium sulphite and sodium hydroxide, which helps to break up some of the natural bonds within the plant cells. Then, the wood is heated and compressed, and its already weakened state leads to the “total collapse of cell walls and complete densification of the natural wood,” according to the researchers.
As the wood is compressed and heated, new bonds form within the super-dense wood, and the result is a material that is both lighter and stronger than most metal metals. Compared to regular, untreated wood, the new material is over 10 times stronger, and up to 20 times as rigid, making it a serious option for construction applications where metals are typically used.
Wood used as a building material can also have a tendency to swell with moisture, decreasing its strength over time and leading to rot. The new, compressed wood is much less prone to swelling and absorption, which is another big plus.
The biggest hurdle for scientists now is developing a process to create the new material on a large scale. In testing, only smaller blocks were produced, and the work to create them took hours. Speeding things up and adapting the technology to huge quantities of wood could be a major challenge, but doing so could result in lots of new options for architects and engineers.
Source: Materials Works Magazine.
Published in Nature https://www.nature.com/articles/nature25476
