Dense "bulletproof" wood

Scientists from the University of Maryland have developed a technology for producing super-strong wood, which can now be used in places where traditionally heavier metals and alloys have been used and are still used. Moreover, the process of creating such super-strong wood is quite simple; it involves pre-treating the wooden blank in a solution of sodium hydroxide and sodium sulfate at the boiling point of water. These chemicals remove lignin and hemicellulose from the wood, substances that are the basis of its structure and give the wood its strength. After such chemical treatment, the wooden block is compressed between two plates heated to 100 degrees Celsius at a pressure of 5 megapascals, which is 50 times greater than normal atmospheric pressure.

As a result of this processing sequence, the volume of the wood decreases by 20 percent relative to its original volume, and the density of the resulting material is three times greater than the initial density. And, thanks to this, the treated dense wood acquires completely new physical properties. It withstands mechanical loads 11.5 times greater, placing it on par with steel in terms of strength, but the treated wood is significantly lighter than steel. For example, to demonstrate the properties acquired by the compressed wood, researchers shot steel balls at it from a pneumatic gun. While these balls passed through untreated wood, they either bounced off or got stuck in the compressed wood board.

The chemicals used to produce engineered wood are not a significant environmental concern. The densification process can be applied to almost any type of wood, from the densest and heaviest varieties to lighter and less dense ones. Researchers believe that the new material could serve as an alternative to steel in situations where environmental cleanliness of constructed buildings and structures is required, for example. Additionally, some vehicle components can be made from this new wood material, which will make them somewhat lighter and consume less fuel or energy.