A recent article at New Scientist tells us about a process to recycle wood, but with a twist: the process not only means you can build something with it again, but it will have more strength than steel.
“This is a really elegant way to heal wood, using a common cellulose solvent, recovering and enhancing the mechanical properties of nature’s wonder material,” says Steve Eichhorn at the University of Bristol, UK. “The approach is evidently scalable and therein lies the challenge to take this technology to the next level.”
The good news is that you don’t need full pieces of wood to build things. Small pieces, broken wood, and even sawdust or pulp can still be treated to create this new material. This can happen because the donor material doesn’t technically continue to be wood. A solvent called dimethylacetamide, used with lithium chloride, can break down the cell walls, releasing lignin, a glue-like chemical in the wood. Tiny fibers in the cell walls are also free to grab other tiny fibers, making for a much harder material than the original wood.
When two or more pieces of wood are stuck together like this, the researchers call it a “healed” piece of wood. It doesn’t look like wood anymore, but preserves some of its best qualities while becoming stronger than steel or titanium alloys.
“We get a mechanical strength that supersedes the strength of the original material,” one researcher told New Scientist. “It works because we use the inherent properties of cellulose, which is a material that binds together very strongly by something called hydrogen bonding.”
Apparently the technology is simple enough to scale up to industrial levels, which would make the process useful for better recycling wood and other wood-based products into this super material.
What Makes This A Great Thing
Steel and other metal production is not only very energy intensive, but often uses coal and other fossil fuels. You need to get metal pretty hot to mix it or shape it, and renewables would really struggle to get the job done. But we need these strong and readily workable materials for many things we do every day, so we can’t do without them. One possible approach to this would be to use hydrogen (which may or may not come from clean sources) to otherwise produce the heat.
Being able to turn to this alternative material could result in far less energy spent to build things, while getting the strength that metal typically has to provide. Wood can be grown again, so it’s renewable. Recycled wood is even better, because you don’t need to cut down any new trees to provide the raw materials for this kind of thing.
The question that I can’t answer at this point is whether the chemical treatment process is energy intensive or otherwise unusually destructive to the environment. If it does have environmental drawbacks, this wouldn’t be a good solution to building tough things. If it can happen with minimal impacts, it would definitely be a great alternative to steel and other metals.
Featured image by Chanan Bos, CleanTechnica.
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