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View Full Version : Valentine's Day Science News: Super Wood


Lonewolf_50
13th Feb 2018, 13:53
OK, it's not really about that kind of wood yet, but who knows what applications "hard as steel" will be derived from the new super material: wood.
https://www.scientificamerican.com/article/stronger-than-steel-able-to-stop-a-speeding-bullet-mdash-it-rsquo-s-super-wood/ Researchers have long tried to enhance its strength, especially by compressing and “densifying” it, says Liangbing Hu, a materials scientist at the University of Maryland, College Park. But densified wood tends to weaken and spring back toward its original size and shape, especially in humid conditions. Now, Hu and his colleagues say they have come up with a better way to densify wood, which theyreport (http://nature.com/articles/doi:10.1038/nature25476) in the February 7 Nature. Their simple, two-step process starts with boiling wood in a solution of sodium hydroxide (NaOH) and sodium sulfite (Na2SO3), a chemical treatment similar to the first step in creating the wood pulp used to make paper. This partially removes lignin and hemicellulose (natural polymers that help stiffen a plant’s cell walls)—but it largely leaves the wood’s cellulose (another natural polymer) intact, Hu says.
The second step is almost as simple as the first: Compressing the treated wood until its cell walls collapse, then maintaining that compression as it is gently heated. The pressure and heat encourage the formation of chemical bonds between large numbers of hydrogen atoms and neighboring atoms in adjacent nanofibers of cellulose, greatly strengthening the material.
The results are impressive. The team’s compressed wood is three times as dense as the untreated substance, Hu says, adding that its resistance to being ripped apart is increased more than 10-fold. It also can become about 50 times more resistant to compression and almost 20 times as stiff. The densified wood is also substantially harder, more scratch-resistant and more impact-resistant. It can be molded into almost any shape. Perhaps most importantly, the densified wood is also moisture-resistant: In lab tests, compressed samples exposed to extreme humidity for more than five days swelled less than 10 percent—and in subsequent tests, Hu says, a simple coat of paint eliminated that swelling entirely. The bit about a coat of paint reducing the swelling is a bit troubling, in the romantic sense. :}

KenV
13th Feb 2018, 14:47
But how resistant is this superwood to termites?

Loose rivets
13th Feb 2018, 15:05
Just an aside:

Ripped son's bathroom wall out in Texas. There they were, thousands of them. Grains of rice with brown heads. Then they started to scream. Yes, in concert. One exact pitch. Totally mind-blowing. My professor son took a video of them, though I rather think folk who didn't know would think it was a prank.



Pre-Vac'd wood is what I used all the time. Suck, soak, re-pressurise.

When I cut the ends I'd dip them in creosote until I'd capillary'd the stuff well above the tide mark.

Not accepting light wood was another ploy. Twenty 11 X 2 joists all weighed about the same - except one. It was exchanged.


Having lived in Texas, I think a lot about building with wood. I'm a bit of a convert. However, some of the techniques used by builders there - and in Tennessee - were bewilderingly bad. Some kind of strong wood is really needed.

A friend in a new build house asked me what I thought about his office floor collapsing towards his triple garage. They'd used a beam made of bits of wood zig-zagged and held together with dog-joints. What an obscenity. My only comment was to suggest he remove the three luxury cars parked underneath.

Another that comes to mind is a $5,000,000 house on the side of a lake in Austin. The house was stunning with copper over the dormer windows. The boat garages had remote control doors of course but where the external (stuccoed) wall met the water, the plaster ended there with chicken wire mesh flapping out of the concrete. The illusion ended at the waterline..

I can see the need for super-wood being in large supply.


Can I TM that name d'yer think?
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KenV
13th Feb 2018, 15:43
It'll be interesting see how this super wood compares performance-wise and cost-wise with the many different engineered wood products now available. Indeed glued laminate wood ("glulam") is already stronger, per pound, than steel. But steel is cheaper. I wonder if this new super wood will be cheaper than glulam and even than steel.

I understand that there's even a transparent wood composite now in the labs, but not yet in production.

Lonewolf_50
13th Feb 2018, 16:29
@KenV There is, but I am not sure when I can buy windows made out of it.

Loose rivets
13th Feb 2018, 23:11
You won't be able to see the trees for the wood.:eek:

ethicalconundrum
13th Feb 2018, 23:25
I never was comfortable much working with wood. Always prefer metal. Building a hangar right now, and using metal. Wonder if I can weld this new kind of wood? Probably not, but it's interesting stuff.

oldpax
13th Feb 2018, 23:44
I remember laughing when I was shown a plastic pipe welding machine!!!

ethicalconundrum
13th Feb 2018, 23:59
I used one of those plastic welders to make a deck for the back of my boat. It worked great once I got the hang of temp and moving the 'torch' right. Sadly, wood doesn't change state from solid to liquid. Wondering if the new stuff does have a melt point? Unlikely, given it's underlying protein based structure.

mushmonster
15th Feb 2018, 06:18
I used one of those plastic welders to make a deck for the back of my boat. It worked great once I got the hang of temp and moving the 'torch' right. Sadly, wood doesn't change state from solid to liquid. Wondering if the new stuff does have a melt point? Unlikely, given it's underlying protein based structure.

It seems unlikely as you’ve said. But I heard that they were working on it. They say it’ll definitely have a melting point in near future, yet I have doubts about it.

ORAC
15th Feb 2018, 11:42
The whole concept goes against the grain....

Argonautical
15th Feb 2018, 16:24
Could be a knotty problem.

lomapaseo
15th Feb 2018, 16:28
gives a new meaning to the term "woody"

Um... lifting...
15th Feb 2018, 17:12
-gwXJsWHupg

ORAC
15th Feb 2018, 17:37
I see it as a growth industry.

KenV
16th Feb 2018, 14:51
Wonder if I can weld this new kind of wood? Probably not, but it's interesting stuff.Weld? Certainly not. But like almost all wood products, there are a wide variety of adhesives available, including adhesives rated for structural applications.

Um... lifting...
16th Feb 2018, 19:40
A renaissance of proper joinery, and pish on their adhesives, which, while having their place, neglect the inherent strength characteristics of wood, in its natural state or otherwise.

Wood has long been used in automobiles for structural coachwork and indeed has been enjoying a renaissance in certain vehicles, the Corvette for one.