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A Chemical Bath and a Hot-press Can Transform Wood Into a Material That is Stronger Than Steel, Researchers Find (nature.com)
The process, and others like it, could make the humble material an eco-friendly alternative to using plastics and metals in the manufacture of cars and buildings, Nature reported this week. From the report: "It's a new class of materials with great potential," says Li Teng, a mechanics specialist at the University of Maryland in College Park and a co-author of the study published on 7 February in Nature. Attempts to strengthen wood go back decades. Some efforts have focused on synthesizing new materials by extracting the nanofibres in cellulose -- the hard natural polymer in the tubular cells that funnel water through plant tissue. Li's team took a different approach: the researchers focused on modifying the porous structure of natural wood. First, they boiled different wood types, including oak, in a solution of sodium hydroxide and sodium sulfite for seven hours. That treatment left the starchy cellulose mostly intact, but created more hollow space in the wood structure by removing some of the surrounding compounds. These included lignin, a polymer that binds the cellulose. Then the team pressed the block -- like a panini sandwich -- at 100C (212F) for a day. The result: a wooden plank one-fifth the thickness, but three times the density of natural wood -- and 11.5 times stronger. Previous attempts to densify wood have improved the strength by a factor of about three to four.
There is also a summary here at Sciences News.
Ceci n'est pas une signature.
Generally solid wood is a good choice for many projects due to three key reasons:
1. Cost
2. Workability; can be worked with hand tools and power tools, glues easily and strong
3. Water safe for years with no significant prep work
Steel is a lot stronger per pound, but to join it you either need to use mechanical fasteners or weld it. This requires expensive ($300+) specialized equipment like a welder and/or drill press. Wooden boats are generally good from 15-20 years without major renovations, and are serviceable with major repairs every 10-15 years up to 60-75 years after initial construction. Steel needs to be galvanized, or painted, or sanded and resurfaced every 2-5 years, especially in a saltwater environment (most of the things in your house arrived from asia in a big steel boat).
Super dense wood that's lost most of it's lignin likely is hyper brittle and doesn't machine well. Also, I can only imagine what happens when it's immersed in water. There's a non-zero chance it swells up like a dry sponge when it comes in contact with water or even regular humidity.
moox. for a new generation.
TFS says:
> Attempts to strengthen wood go back decades.
Decades? Really? People have been firing wood and embedding carbon into its surfaces for at least 400,000 years. This author is off by at least four orders of magnitude.
You just invented plywood!
Plywood is weaker than normal wood not stronger and definitely not stronger than steel.
Not when sandwiched vertically in a weight-bearing truss.
Happiness in intelligent people is the rarest thing I know.
Ernest Hemingway
just recycling an infinitely renewable inorganic compound or metal?
I never followed that "logic".
Trees grow ridiculously slowly. And no, you can't just plant a few fast-growers (in a mono-culture even) and call it the same as an ancient complex forest eco system that sustained tens of thousands of species in an elegant balance of cycles!
Meanwhile, metals and generally crystals and materials made from ore are easily recycled in a single day, with some smelting and forging, using only solar energy from places where nothing lives anyway.
"Stronger than steel" is silly anyway. Steel is not very strong. And what do you mean with that word anyway? There's half dozen things that that can mean, and in none is steel quite the best we have. Steel is only popular, because it is very abundant and very cheap, with acceptable properties.
Using trees for building things (apart from decorative furniture and the likes) is as stupid as using fields to grow crops to then turn them into gasoline instead of food.
Then the team pressed the block -- like a panini sandwich -- at 100C
People who read news for nerds might not be able understand what pressing a block means in this context. A highly accurate and technical description, make it so readily comprehensible. Like a panini sandwich! Good, someone might mistake pressed the block something like a burger or a calzone. One might even be thinking of pasta or pilaf or masala dosa. Now it is clear. Press the block like a panini sandwich. Good. Great job.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
Trabants were partially made of plywood, weren't they?
Yes. Also, many WW2-era German, Russian, and British aircraft of many types including fighters, especially early in the war for the Soviets and late in the war for the Germans, used various types of laminated and/or compressed wood, some as a major percentage of the vehicle. The British Mosquito was one of the fastest aircraft in the WW2 sky and made the first bombing runs on Berlin due to it's speed, payload capacity, long range, and was made largely from wood. It served many different roles from heavy fighter, to twin-engine fast bomber, to fast reconnaissance, and more. Pilots loved the "Mossy". It was such a great aircraft the Germans tried to copy it, but with only limited success.
Strat
Progressivism (aka US 'Liberalism'): Ideas so good they need a police/surveillance-state to enforce.
In WW2 the British built a multi-role military aircraft called the "Mosquito" out of plywood. Originally conceived as a very fast lightweight bomber, it was a brilliant success at a wide variety of tasks: night fighter, high altitude interceptor, ground attack craft, photo-reconnaissance craft, torpedo bomber.
Basically it was the anti-F35: designed to do one thing well, it ended up doing everything pretty well.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
The chassis of Morgan sports cars (just about all that remains of the UK owned car industry) are still made of ash.
Note that "strength" in this context is per cross sectional area. So taking a block of wood, and compressing it down doesn't change its absolute strength (it can support the same weight as before), but increases its measured strength (load per square mm of cross sectional area before failure). One of the attractions of metals like steel is their isotropic properties - they have the same properties regardless of which direction you load them. Fibrous materials are anisotropic - stronger in certain directions than others.
Glass fibers are also stronger than steel in tension, but they're weaker in compression and absolutely suck in shear (loading perpendicular to the fibers). The fibers just bend sideways instead of offering any resistance. So we embed them in a matrix of plastic (polyester or epoxy) to create fiberglass. Tensile and compressive strength are reduced, but shear strength improves substantially - enough to where you can walk on a fiberglass board whereas raw glass fibers would simply flop over and let you fall through. Where a fiber used to bend, the plastic matrix absorbs and transmits those forces to other fibers, converting shear forces into tension and compression (the board bows downward in the middle, compressing in the top half, stretching in the bottom half).
It sounds like what this team has done is taken wood, and cooked it so the cellulose fibers remain but much of the matrix which holds them together has been removed. That has little consequence in tension, but could weaken shear strength to where the material is structurally useless except as rope/cable.
You're right in that wood does not bend and collapse the way steel does. But what it does do is **feed the fire**. Even wood treated to be less flammable still burns more easily than steel does. (and gives off toxic smoke once the fire overwhelms the chemical resistance. When the wood studs and joists in a home are burned to more than something like 15% of their cross section, they can no longer be expected to carry the load. Wood framed structures collapse more readily than the equivalently steel framed structure. (Note: I am not referring to the thin steel wall studs used to build partition walls, those are never intended to carry any load beyond the weight of the drywall mounted on it. Even a small twist caused by the collapse of an adjoining area totally destroys any load bearing capacity the studs have)
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Oh, it gets much better than that. From Wikipedia:
Similar to fiberglass, Duroplast has limited possibilities for efficient disposal. As discarded Trabants began to fill junkyards, disposing of the bodies inspired creative solutions. One of these was developed by a Berlin biotechnology company, who experimented with a bacterium that would consume the body in 20 days.[2][3] Urban legends, depicted in the movie Black Cat White Cat and described in a song by the Serbian band Atheist Rap, described recycling Duroplast by
feeding the cars to pigs, sheep and other farm animals.
Duroplast flavored bacon? Yum, yum!
After the Berlin Wall fell, Germans voted with their wallets on how they felt about Duraplast cars. Although, the Trabi was overall a crappy car, so it wasn't just the Duroplast. It's amusing that just across the border, the West Germans were building BMWs and Porsches.
That shows you how bad communism is. Under communism, you can take take a nation of Germans, and only make crappy cars with them.
Schroedinger's Brexit: The UK is both in and out of the EU at the same time!
Yes and no. The 2x4s used in standard residential framing burn quite readily. Larger timbers form a protective char, which, as long as it remains on the wood, protects the inner core from fire. If the timber has been specced correctly, the char does not penetrate deeply enough to compromise the structure for some time.
Steel, meanwhile, is an excellent heat conductor and therefore will start to sag as soon as the outer edge of the steel has reached a temperature that will cause sag.
Looks like the chassis is metal but the frame is ash:
https://www.classicdriver.com/...
An indication of just how good the Mosquito performed is the grudging admiration of Hermann Göring:
In 1940 I could at least fly as far as Glasgow in most of my aircraft, but not now! It makes me furious when I see the Mosquito. I turn green and yellow with envy. The British, who can afford aluminium better than we can, knock together a beautiful wooden aircraft that every piano factory over there is building, and they give it a speed which they have now increased yet again. What do you make of that? There is nothing the British do not have. They have the geniuses and we have the nincompoops. After the war is over I'm going to buy a British radio set – then at least I'll own something that has always worked.
So in modern marketing terminology, it was an advanced biopolymer composite. ;)
Ezekiel 23:20