Scientists Develop Transparent Wood That Is Stronger, Lighter Than Glass (www.cbc.ca) 91
Researchers at the University of Maryland have turned ordinary sheets of wood into transparent material that is nearly as clear as glass, but stronger and with better insulating properties. It could become an energy efficient building material in the future. CBC.ca reports: Wood is made of two basic ingredients: cellulose, which are tiny fibres, and lignin, which bonds those fibres together to give it strength. Tear a paper towel in half and look closely along the edge. You will see the little cellulose fibres sticking up. Lignin is a glue-like material that bonds the fibres together, a little like the plastic resin in fibreglass or carbon fibre. The lignin also contains molecules called chromophores, which give the wood its brown colour and prevent light from passing through.
Early attempts to make transparent wood involved removing the lignin, but this involved hazardous chemicals, high temperatures and a lot of time, making the product expensive and somewhat brittle. The new technique is so cheap and easy it could literally be done in a backyard. Starting with planks of wood a metre long and one millimetre thick, the scientists simply brushed on a solution of hydrogen peroxide using an ordinary paint brush. When left in the sun, or under a UV lamp for an hour or so, the peroxide bleached out the brown chromophores but left the lignin intact, so the wood turned white.
Next, they infused the wood with a tough transparent epoxy designed for marine use, which filled in the spaces and pores in the wood and then hardened. This made the white wood transparent. You can see a similar effect by taking that same piece of paper towel, dip half of it in water and place it on a patterned surface. The white paper towel will become translucent with light passing through the water and cellulose fibres without being scattered by refraction. The epoxy in the wood does an even better job, allowing 90 per cent of visible light to pass through. The result is a long piece of what looks like glass, with the strength and flexibility of wood. The findings have been published in the journal Science Advances.
Early attempts to make transparent wood involved removing the lignin, but this involved hazardous chemicals, high temperatures and a lot of time, making the product expensive and somewhat brittle. The new technique is so cheap and easy it could literally be done in a backyard. Starting with planks of wood a metre long and one millimetre thick, the scientists simply brushed on a solution of hydrogen peroxide using an ordinary paint brush. When left in the sun, or under a UV lamp for an hour or so, the peroxide bleached out the brown chromophores but left the lignin intact, so the wood turned white.
Next, they infused the wood with a tough transparent epoxy designed for marine use, which filled in the spaces and pores in the wood and then hardened. This made the white wood transparent. You can see a similar effect by taking that same piece of paper towel, dip half of it in water and place it on a patterned surface. The white paper towel will become translucent with light passing through the water and cellulose fibres without being scattered by refraction. The epoxy in the wood does an even better job, allowing 90 per cent of visible light to pass through. The result is a long piece of what looks like glass, with the strength and flexibility of wood. The findings have been published in the journal Science Advances.
Not good enough. (Score:5, Funny)
We need transparent aluminum, not transparent wood.
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Fire! Fire bad! -- (technically) Frankenstein's monster
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Re:Not good enough. (Score:4, Insightful)
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Well, it's certainly a composite. But nothing wrong with that. Clarity looks too low for home windows and the like, but should be fine for skylights and greenhouses and the like (with greenhouses, you actually want some scattering**, so long as transmission remains high). Question as to how durable it is. At least the fibres should be very UV resistant.
** The sun being an effective point source is very inconvenient for plants. Photosynthesis saturates in the upper leaves, the plant often being unable to u
Re: Not good enough. (Score:4, Informative)
Re: Not good enough. (Score:4, Informative)
yeah ALON is basically a ceramic. Unlike traditional aluminum, it's pretty hard so it doesn't flex, and that makes it a completely different sort of material.
It would be more appropriate to call it "transparent ceramic".
Re: Not good enough. (Score:2)
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Not to mention that construction with transparent wood could be done with the hammer, nails, and saw already on site given the right resin. Also less tendency to break when treated like other construction materials. There's a reason the windows go into a house as late in the building as practical.
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We need transparent aluminum, not transparent wood.
It exists and is called Aluminium oxynitride. Very expensive https://en.wikipedia.org/wiki/... [wikipedia.org]
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It is not non-flammable. (Score:5, Informative)
It is still wood soaked in (rather pricey [aeromarineproducts.com]) epoxy.
I.e. It still burns.
It doesn't seem to self-ignite, like nitrocellulose though.
As such, it may find a niche in interior design, furniture production and as a hobby material. But I doubt that it will be hailed as new building material.
If we're gonna soak wood in epoxy in order to make blurry windows out of it, might as well laminate glass and have bulletproof windows.
In either case, you're fucked if you do need to break that glass in case of fire. Only now that window also burns as you're chopping it up with an axe, trying to break out.
But it might work as a detailing material for furniture.
Link to TFS. [sciencemag.org]
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Cured epoxy isn't flammable, and the cellulose fibers embedded in it won't have access to atmospheric oxygen so it's going to be really difficult to burn this stuff. It certainly won't catch on fire the way untreated wood will. Given enough heat it'll likely turn black, start to sag and produce nasty fumes.
The reason why this will not be used in windows is that windows need to be thicker than one millimeter, and you need multiple panes for insulation. You could barely see through it. If you want a plastic w
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Seems to me a good use for it is skylights, clerstory windows, and the like, where you want max light but don't need a perfectly clear view. Whether it's worth replacing existing plastic panels? Well, it sure would be nice to have more light (and less heat loss) from my barn's skylights than I can get from patio plastic. Better than plexiglas? Maybe more durable under insults like hail and building flex.
Anyway, an interesting material, but as you say so far practical use seems limited, especially at the pri
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Old reels of celluloid movie film combined with 30% hydrogen peroxide used to be a favorite rocket fuel among hobbyists in the 1950s.
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Yeah, and epoxy was always stronger and lighter than glass...
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Celluloid is made from nitrocellulose. AKA guncotton. It is violently flammable and in thin films or powdered it can explode. That's why it was replaced by acetate in filmstock in the '50s.
Re: Not good enough. (Score:4, Funny)
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Epoxy can solve that problem, too!
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It is actually done:
https://ceramics.org/ceramic-t... [ceramics.org]
Star Trek has pioneered many ideas, and some crazy scientist have actually made the transparent aluminum into reality!
Don't do that (Score:3)
Just bleached wood with epoxy, move along (Score:2, Interesting)
Been done before funnily enough. It's not transparent wood, it's transparent epoxy, with some wood.
Same effect with miss wet t-shirt, but instead of water, you used epoxy, so ya, nothing new and not wood.
Re: Just bleached wood with epoxy, move along (Score:5, Informative)
Did you bother to read what you linked to and the article here?
Yes, transparent wood has been known for a while and us "old news". The article here is about being able to make transparent wood in an environmentally friendly fashion. The bleaching here is with hydrogen peroxide and UV light. Waste product from that is water. The article you linked used far more harmful chemicals that are hard to dispose if safely.
I know this is slashdot, but could you actually read the article before spewing garbage?
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Did you read the headline here before spewing garbage?
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Did you read the headline here before spewing garbage?
The headline mentions it is stronger than glass. The old version of transparent wood wasn't as strong, because instead of bleaching the lignin, they old method removed it. So, yes, this is a novel thing. Hell, the second paragraph of the summary mentions that transparent wood has been made before and why this wood is different. So saying, "Common knowledge since 2016. Hardly news." is a sign someone didn't even read the summary before pissing on the story.
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It's stronger than glass because it's wood fiber-impregnated epoxy. It's sustainability given the epoxy base, becomes more questionable. The transparency is nice, but much dried epoxy is also translucent/transparent.
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That process removes the lignin rather than bleaching it.
A lot more to the wet t-shirt effect (Score:2)
The point of the wet t-shirt is that it isn't completely transparent -- it still leaves a little bit to the imagination, which, to excuse a pun, is the whole point of it.
Re: Home science project (Score:3)
Iâ(TM)m not sure this would be a good home science project.
First, where are you going to get 1mm thick wood? Even most veneers are 2-3mm.
Second, the article didnâ(TM)t mention the concentration of hydrogen peroxide they used. Sure, you can find upto 35% if you look hard enough, but at the high end of that itâ(TM)s considered a hazardous material so youâ(TM)re not getting it from Amazon. I have a feeling drug store 3% wouldnâ(TM)t t cut it and I wouldnâ(TM)t let kids play with 1
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Second, the article didnÃ(TM)t mention the concentration of hydrogen peroxide they used.
Wow. It says right in the fine paper [sciencemag.org] that "Sodium hydroxide (NaOH) (Carolina Biological Supply Company), hydrogen peroxide (H2O2, 30% solution; EMD Millipore Corporation), and UV lamp (380 to 395 nm of wavelength; China) were used for lignin modification of the balsa wood." I guess clicking a link and searching for "perox" is a lot of work by modern standards huh?
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Ok, I just looked at the linked article from CBC.ca which didn’t mention the concentration so I willll give you the lazy critique.
My remark still holds though, you definitely don’t want to be playing with 30% in the back yard with the kids.
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Agreed. Handing the little buggers some low grade rocket fuel is probably a bad plan.
I wonder if you could do it with sufficient exposure to lower-grade stuff, though.
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Balsa wood? 1mm thick balsa wood is almost transparent on its own already. I thought this was non-news news to start with, now even more so.
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While 1mm of wood is possible, but you are going to need a good straight piece of wood, and a well tuned table saw.
However to get that 1mm of wood, you are probably going to waste about 13mm of wood. With the jointing, planing, and the normal table saw has a 1/8 inch kerf.
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no one is using a table saw to make veneers in commercial quantities. I can get awfully thin blades for my band saw, and I can resaw wood that is larger than 4" in width, too. My bandsaw will happily resaw a pice of wood that is 14" tall, 18" thick, and as long as I can reasonably push through the blade, and all with a blade that is about 1/32 of an inch thick.
Now do it without making wood non-recyclable (Score:3)
That's just plastic with extra steps and not recyclable.
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That's what i thought too. This is an epoxy composite, or epoxy strengthened with wood fibers.
The ratio wood/epoxy is barely irrelevant, though i bet it'll soak vast amounts of epoxy. And the result is poorly recyclable, which is an understatement as it's almost chemical waste that needs to be burned at elevated temperatures, whereas glass is easy recyclable.
Only if durability is excessive high it might have a purpose, but that's doubtful too, as epoxy is not immune to weathering and the wood fibers surely
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Apparently it's balsa wood, so durability is not in the cards either.
Retrobright (Score:2)
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8Bit Guy to the rescue :) :)
Now LGR can build a transparent wood grain PC case
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I for one welcome flammable windows. (Score:2)
Especially ones that smell like epoxy.
Interesting Engineered Wood Product (Score:5, Interesting)
This appears to be a new engineered wood product to add to the growing range of wood-based construction materials. Although dimensional lumber is commonly used for framing nearly all wood construction otherwise relies on engineered wood like plywood, oriented strand board (or most cheaply particle board). The stronger materials - plywood and OSB - are made by slicing lumber thin and using polymers to glue it back together in various ways to enhance its mechanical properties.
Skyscrapers are going up around the world now made of newer engineered wood products like Glulam [moelven.com] and Cross-Laminated Timber [apawood.org].
This material is 43% wood fiber by volume, and is about as strong as regular plywood, and stronger than the epoxy itself. It is a type of semi-natural composite material in which all of the reinforcing fiber is natural wood. A good use of a material would be in ceiling and wall panels where much heavier diffusing glass or other polymer product would be used. And any such usage locks up carbon from the atmosphere.
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Skyscrapers are going up around the world now made of newer engineered wood products like Glulam and Cross-Laminated Timber.
Neither of those things are remotely new.
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Skyscrapers are going up around the world now made of newer engineered wood products like Glulam and Cross-Laminated Timber.
Neither of those things are remotely new.
From Wikipedia:
CLT was first developed and used in Germany and Austria in the early 1990s. Austrian-born researcher Gerhard Schickhofer presented his PhD thesis research on CLT in 1994. Austria published the first national CLT guidelines in 2002, based on Schickhofer's extensive research. These national guidelines, "Holzmassivbauweise", are credited with paving a path for the acceptance of engineered elements in multistory buildings. Gerhard Schickhofer was awarded the 2019 Marcus Wallenberg Prize for his groundbreaking contributions in the field of CLT research. By the 2000s CLT saw much wider usage in Europe, being used in various building systems such as single-family and multi-story housing. As old growth timber become more difficult to source, CLT and other engineered wood products appeared on the market.
So... only in commercial use less than 20 years and undergoing expanding adoption right now. Wood has been in use by humans as long as humans have existed, lets be Homo sapiens sapiens centric and say 250,000 years. Your definition of "remotely new"?
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Plywood is cross-laminated timber. It's just thinner.
The alleged invention of CLT in the 1990s is only "making plywood thicker".
Further, I don't believe these techniques weren't used long before. It's not like they didn't have glue for ages.
Re: Interesting Engineered Wood Product (Score:1)
And epoxy is so environmentally friendly.
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In fact in can be. There are green epoxy resin plants in existence right now that derive their feedstocks from plant based sources (e.g. epichlorhydrin raw material from glycerin). And even at the worst, the petrochemical produced resins are not putting carbon and other pollutants into the air like burning it does.
I notice that none of the snide posts here have any links or facts to back them up. But ignorant drive-by snarking is as much a SlashDot tradition as being an an anonymous coward or refusing to re
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And any such usage locks up carbon from the atmosphere.
There's no way all those processed materials have a smaller footprint than using unprocessed (dimensional) lumber. Yes. "engineered" lumber products have their advantages; let's not get carried away.
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There's no way all those processed materials have a smaller footprint than using unprocessed (dimensional) lumber.
You have to remember you need a lot more dimensional lumber to get the same strength, usually in sizes that are impossible or require an exceptionally old tree.
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You mean - without doing any research at all on the subject, or putting any real thought into it you imagine "there's no way".
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I'm curious on how thick they can make it, and what the R value would be. If it's a better insulator than glass, you could very rapidly see its applications in green buildings.
Though, let's not use this as an excuse to bring back "glass" blocks ;).
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The R value of wood is about 1.25/inch.
An R value of a triple-pane window is something like 7-8. A double-pane window is about 3.5-4.
It's normal to build exterior walls out of 2x6s these days in order to fit enough insulation in the walls. So assuming this stuff becomes the "windows" in that wall and are the same thickness of the wall, and the epoxy doesn't reduce the R value much, then the R value would be about the same as that triple-pane window.
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They making this 1 mm thick, basically a single ply similar to high quality plywood like Baltic birch. You could laminate this material together into multiple plies, but using a light single layer might be best for interior use, or doing double pane construction like regular windows for its insulation value.
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This would have an R-value somewhat worse than untreated wood. Better than glass, but that isn't saying much. In any case the R-value of the material itself is almost irrelevant when it comes to windows - at the thickness of a window pane, there's very little resistance to conductive heat flow*. The R-value of window units comes from having multiple panes with gaps in between filled with a gas.
*For example, if this material has the same R/inch as wood then a 3mm pane would have an R-value of 0.15. This is b
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Epoxy outdoor lifespan before breaking down is 10-20 years, glass is infinite by comparison. Sure you could paint it but then this is supposed to remain transparent.
My wood furniture also locks up carbon from the atmosphere. It is 99% percent wood. - In fact the firewood I have sitting in a dry location is currently locking up carbon too.
All this plastic embedded wood, it may look better longer than classic wood but how m
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Epoxy outdoor lifespan before breaking down is 10-20 years,.
Says the guy just making stuff up.
Epoxy does require a UV blocking coatings outside, but very thin clear UV blocking coatings are ubiquitous (benzophenone containing polyolefins for example) so this has been a solved problem for at least 70 years. Epoxy is used to construct aircraft bodies, ocean-going boat hull, outdoor floorings, etc. with many, many decades of service life.
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If something is only a minority of wood by mass, can we really call it wood?
I have a genuine wood gear-shifter in my car, is my car wooden?
This is cellulose-reinforced epoxy. "Semi natural" is a stretch. Hell, you could probably lay textile threads in epoxy and get BASICALLY the same improvement in strength - after all, that's more or less what carbon fiber laminate is.
1 mm thick "plank"? (Score:1)
Can't see the transparent forest for the trees (Score:1)
An epoxy window... how novel (Score:1)
Pity about the waste of wood
But 1mm is so thin (Score:3)
Not stronger at all (Score:3)
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There are several types of strength in engineering, I'm sure wood has at least one of those over glass.
Three types of tensile strength (yield, breakable and ultimate), impact and compressive.
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Glulam (Score:1)
Wow! (Score:2)
well, probably not in your backyard (Score:1)
Reinforced Epoxy (Score:2)
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From the article:
The clear wood is lighter than glass, with better insulating properties, which is important because windows are a major source of heat loss in buildings.
It's more insulating, not less. That isn't surprising. Glass is a terrible insulator, or to put it the other way, it conducts heat really well. That's why modern windows are double paned. Trap a layer of air, which is a much better insulator, between two pieces of glass.
GMO (Score:1)
A bit misleading... (Score:1)
Obligatory sarcasm follows (Score:2)
This for people who can't see the forest for the trees.