A while back, CleanTechnica was taking stock of all the bio-based materials coming on to the automotive scene, and here comes yet another entry. A research team at the University of Maryland has developed a wood-based material that can compete with steel in the strength category. That sure could put the wood back in “woodie” when it comes to using renewable materials to manufacture cars and other vehicles, so let’s take a look.
The Return Of Wooden Cars? Maybe!
Cars used to be made with wood back in the horseless carriage days, but then steel happened and the rest is history.
And, maybe history will repeat itself.
The new wood-based material is reportedly as strong as steel but six times lighter, which is why all the excitement about using it to build cars.
As a special sustainability bonus, you don’t have to start out with a hardwood to make this extra hard wood.
According to the research team, fast-growing soft woods will do the trick. So for example, you wouldn’t need to put those pine tree shaped air fresheners in cars, because cars would already be pine trees. The team also suggests balsa as a sustainable source.
The secret is compressing the wood after removing the lignin (the tough part that “glues” wood cells together). The remaining material is packed in so closely that it forms strong hydrogen bonds, “like a crowd of people who can’t budge — who are also holding hands,” as UMD describes it.
The research team deployed a deceptively simple process to create the new material. You could DIY this at home with the right equipment:
The team’s process begins by removing the wood’s lignin, the part of the wood that makes it both rigid and brown in color. Then it is compressed under mild heat, at about 150 F. This causes the cellulose fibers to become very tightly packed. Any defects like holes or knots are crushed together. The treatment process was extended a little further with a coat of paint.
Well, maybe not. The tricky part is to get the amount of lignin down to just the right concentration:
Too little or too much removal lower the strength compared to a maximum value achieved at intermediate or partial lignin removal. This reveals the subtle balance between hydrogen bonding and the adhesion imparted by such polyphenolic compound.
If you are a legal gun owner you could replicate part of the test process but then again maybe that’s not such a great idea either:
The team tested their new wood material and natural wood by shooting bullet-like projectiles at it. The projectile blew straight through the natural wood. The fully treated wood stopped the projectile partway through.
For more details check out the research paper, “Processing bulk natural wood into a high-performance structural material” in the journal Nature. The research team was led by Liangbing Hu with co-leader Teng Li, and included Jianwei Song, Chaoji Chen, Shuze Zhu, Mingwei Zhu, Jiaqi Dai, Upamanyu Ray, Yiju Li, Yudi Kuang, Yongfeng Li, Nelson Quispe, Yonggang Yao, Amy Gong, Ulrich H. Leiste, Hugh A. Bruck, J. Y. Zhu, Azhar Vellore, Heng Li, Marilyn L. Minus, Zheng Jia, and Ashlie Martini.
And yes, the team is already anticipating that their high tech wood could be used to manufacture cars.
One Step Closer To Compostable Cars
Okay so we’re really not all that close to being able to throw our cars in the compost when they die, but we’re getting closer.
Bio-based plastics are already a thing, and Ford has taken up a leadership role in producing the bio-based cars of the future. Aside from mix-and-match materials like a wood-reinforced polymer, the company’s list of natural ingredients includes everything from shredded paper to used denim, with agave fiber and dandelions in between.
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Image: “Liangbing Hu (left) holds a block of wood transformed by a new process to become stronger than rivals titanium & tougher than steel. Teng Li (right) holds an untreated block of the same wood” via University of Maryland.