Wood is a pretty awesome material, but it’s certainly lacking the strength and toughness of other materials such as the stronger metals. That could change, however, thanks to research coming out the University of Maryland, College Park, where engineers have found a way to make wood more than 10 times stronger than titanium alloys.
The results mean that everyone’s favorite tree-based material could be used as an alternative to the ultra-tough likes of steel while remaining significantly lighter. Faster growing softwoods like pine and balsa could also be treated to replace some of the applications which currently require slower growing but denser woods like teak.
“We [developed] a totally new densification technique by combining chemical modification and hot-pressing,” Liangbing Hu, the leader of the research team, told Digital Trends. “Our resulting densified wood features a highly dense and laminated structure with intertwined cell walls that are fully collapsed without gaps. Most of the densified wood consists of well-aligned cellulose nanofibres, which greatly enhance hydrogen bond formation among neighboring nanofibres. The mechanical performance of the resulting densified wood is more than one order of magnitude better than that of the natural wood.”
The chemical modification Hu refers to involves partially remove lignin, the organic polymer that forms an important structural material in plants, and hemicellulose, a component in plant cell walls. The densification technique was then completed by hot-pressing to a temperature of 100 degrees Celsius.
To put the new material through its paces, the team tested its resilience to bullet-like projectiles by firing at it. While the projectile was able to completely pierce natural wood, in the case of the new reinforced wood material it only penetrated part of the way through.
“We are [currently] investigating its potential integrations into multiple applications which requires the material to meet the complete performance matrix,” Hu said, concerning the next step of the project. A University of Maryland startup called “Inventwood” has been created to help commercialize the university’s advanced wood technologies, including this one.
A research paper on the work, titled “Processing bulk natural wood into a high-performance structural material,” was recently published in the journal Nature.
