Material made from recycled wood can be five times stronger than that of natural wood. It can also be made from any timber waste, such as shavings or sawdust.
Although natural wood is an extremely versatile material every year millions of tonnes end up in landfills. Wood must be re-used on an even larger scale in order to create a truly circular economy.
Orlando Rojas from the University of British Columbia (Canada) has developed a process to dissolve lignin, a gluelike component within plant cell walls. This exposes cellulose nanofibrils which are small fibers also found inside the plant cell wall. This method uses a solvent called dimethylacetamide in conjunction with lithium chloride.
The nanofibrils bond to form what researchers call a “healed piece” of wood when two pieces of natural wood are treated in this manner. This wood is not the same as natural wood but has superior mechanical properties. It is stronger than steel and titanium alloys in breaking resistance, according to tests.
Rojas says that Rojas achieves a mechanical strength that exceeds the original material’s. It works because we use the inherent characteristics of cellulose, which is a material that binds together very strongly through something called hydrogen bonding.
The Natural Wood treated in this manner can be reused to make new objects. The treatment can also be repeated on the same wood pieces to prolong their useful life.
“This is an elegant way to heal wood using a common solvent, recovering and improving the mechanical properties of nature’s wonder material,” states Steve Eichhorn from the University of Bristol. The approach is clearly scalable, and that’s where the challenge lies in taking this technology to the next stage.
Rojas and his colleagues didn’t look at the cost of their method if it was scaled up to an industrial scale, but they all use well-known techniques. Rojas says that the processes used here are very common in wood processing. “So, scalability does not pose a problem.”