Researchers Found a Greener Way to Bend Wood Into Almost Any Shape

A cellulose-derived solvent temporarily softens wood, letting it bend and harden again.

Try forcing a thin wooden sheet around a tight curve and its fibers will eventually split. But researchers in Italy have found a way to temporarily make wood far more pliable, allowing it to bend into pronounced curves before hardening again in its new shape. While under treatment, the wood has an almost plastic-like flexibility to it, although not quite.

The method uses water mixed with Cyrene, a solvent made from cellulose. Rather than stripping away major components of wood or adding synthetic polymers, the treatment temporarily loosens the material from within. Once the solvent is removed, the wood largely recovers its stiffness while keeping the imposed geometry.

If the method can be scaled by industry, it could prove highly useful in making novel curved wooden furniture, interiors, toys and musical instruments without relying as heavily on intensive machining, high-temperature processing or petrochemical adhesives.

Making a rigid material temporarily soft

At microscopic scales, wood resembles a reinforced composite. Stiff, crystalline cellulose fibers provide much of its strength, while lignin and hemicellulose form a surrounding matrix. Water can soften parts of that matrix, but it has more difficulty penetrating lignin and does relatively little to crystalline cellulose.

Cyrene, a biomass-derived solvent, has attracted attention as a potential alternative to hazardous petroleum-derived solvents. For instance, a 2022 review in Green Chemistry described applications ranging from organic synthesis to materials chemistry.

The researchers found that Cyrene worked particularly well when mixed with water and then used to treat wood. Their measurements suggest the blend increased molecular motion in lignin and hemicellulose while also disturbing the orderly packing of cellulose chains — enough to make the whole wood structure easier to deform without dismantling it.

A roughly 50-50 mixture produced especially flexible wood. In bending tests, treated basswood reached 3.5 percent strain along the grain and 13.9 percent across it, increases of 21 and 23 percent compared with wood treated only with water. Pure Cyrene, intriguingly, had almost the opposite effect: it made wet wood stiffer and less flexible.

After drying, the structural changes largely disappeared, but the wood’s shape was locked in the shape it was deformed into while under treatment. Chemical and X-ray measurements showed no detectable loss of lignin or lasting disruption of cellulose structure, and mechanical tests found no overall deterioration in load-bearing performance.

×

Get smarter every day...

Stay ahead with ZME Science and subscribe.

Daily Newsletter
The science you need to know, every weekday.

Weekly Newsletter
A week in science, all in one place. Sends every Sunday.
No spam, ever. Unsubscribe anytime. Review our Privacy Policy.

Thank you! One more thing...

Please check your inbox and confirm your subscription.

RelatedPosts

Citrus fruit stands poised to make transparent wood more sustainable, stronger, and more transparent
Skyscrapers made out of wood: a feeble idea or a mark of the future?
Scientists make transparent, fireproof glass-like material out of bamboo
World’s first wooden satellite is set for launch. Here’s why this is a pretty big deal

“Our method moves precisely in this direction: it makes it possible to bend wood sustainably and with low energy consumption, without compromising either its natural mechanical properties or its biodegradability,” said Martina Nardi, a researcher at the Italian Institute of Technology.

A different route to moldable wood

Scientists have been trying for years to make wood more shapeable without giving up its useful mechanical properties. A 2021 study in Science, for instance, partially broke down lignin and then used a rapid “water shock” to produce wood that could be folded into three-dimensional structures. The resulting material was remarkably strong, but the treatment deliberately remodeled the cell walls.

The new approach aims instead to preserve wood’s existing architecture and make the change temporary.

However, this particular experiment mostly involved thin sheets, from about one to five millimeters thick, and the laboratory process still required heating, solvent exchange and drying. In industry, you’d have to use much thicker wood. The researchers also have not yet performed full life-cycle or techno-economic analyses, which will be needed before claims of lower environmental impact can be quantified.

For now, its most striking achievement is making intact wood behave, briefly, like a material it normally is not — soft enough to reshape, then strong enough to stay that way.

The findings appeared in Nature’s Communications Materials.