Superdense wood is lightweight, but strong as steel

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Scientists from the University of Maryland have developed a technology for manufacturing heavy-duty wood, which can now be used in places where heavier metals and alloys have been traditionally used and are now used.

Scientists from the University of Maryland have developed a technology for manufacturing heavy-duty wood, which can now be used in places where heavier metals and alloys have been traditionally used and are now used. Moreover, the process of creating such heavy-duty wood is quite simple, it consists in pre-processing the wooden workpiece in a solution of sodium hydroxide and sodium sulfate at a boiling point of water. These chemicals remove lignin and hemicellulose from the tree, the substances that are the basis of its structure and give the tree its strength. After such a 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 higher than normal atmospheric pressure.

As a result of the sequence of such processing, the volume of the tree is reduced by 20 percent relative to its original volume, and the density of the resulting material is three times higher than the original density. And, thanks to this, the processed dense tree acquires completely new physical properties. It withstands 11.5 times greater mechanical loads, which puts it on a level with steel in strength, but the treated wood, at the same time, is much lighter than steel. For an example of the properties acquired by a compacted tree, the researchers fired at it with steel balls released from airguns. And if these balls passed right through the untreated tree, then they either bounced off the compacted wood board or got stuck in this board.

The chemicals used to produce compacted wood are not a significant environmental problem. At the same time, almost any type of wood is exposed to the compaction process, starting from the most dense and heavy varieties and ending with lightweight and less dense varieties. Researchers believe that the new material may become an alternative to the use of steel where compliance with the environmental friendliness of the buildings and structures being built, for example, is required. In addition, some components of vehicles can be made of new wooden material, which will thereby become somewhat lighter and will consume less fuel or energy.

Source: https://www.sciencenews.org/article/superdense-wood-lightweight-strong-steel