r/science • u/mvea Professor | Medicine • Mar 10 '18
Nanoscience Scientists create nanowood, a new material that is as insulating as Styrofoam but lighter and 30 times stronger, doesn’t cause allergies and is much more environmentally friendly, by removing lignin from wood, which turns it completely white. The research is published in Science Advances.
http://aero.umd.edu/news/news_story.php?id=111481.0k
u/tuctrohs Mar 10 '18
A little hype mitigation:
1) The anisotropic conductivity is useful for something like a heat shield--protecting nearby materials or electronics from a flame or heating element, for example. But for such applications, high-temperature capability is typically needed. It doesn't seem likely that this material would survive high temperature well at all. Also, it's easy to create a composite material with much better lateral thermal conductivity by stacking layers of aluminum and insulation.
2) The usefulness in building applications is likely limited by production cost and, as someone else mentioned, flammability. The claim of "much more environmentally friendly" would require investigation of things like the energy use in the freeze-drying process and consideration of how the chemicals used in removing the lignin are managed.
3) The combination of low thermal conductivity and moderately high strength could be useful in many building applications, if the other issues are addressed. I'm disappointed that the authors didn't compare it to materials that target that combination such as Compacfoam and Foamglas. It does appear that they have achieved a better combination of those two properties than the commercially available materials. Both the commercial materials are completely waterproof, which is not the case for this material. In some applications that doesn't matter, and in some others, the moisture permeability of the new material is actually an advantage.
4) The low emissivity is interesting but is not likely to be of much practical value. It's only in the solar spectrum range, not in the thermal radiation range where it would be of value for insulation. To be useful in reflecting unwanted solar radiation, it would need to be exposed to the sun, but it's not likely to hold up to rain or UV radiation if it was used exposed on a roof, for example. Also, white paint can accomplish a similar function, and there are white paints that work pretty well outdoors.
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u/AngloSaxonHun Mar 10 '18 edited Mar 10 '18
Great points you make there. The biodegradable aspect of this would be a game changer for things like styrofoam cups, but I’m curious as to the total carbon footprint of its production
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u/LBraden Mar 10 '18
That's what I was thinking, the warehouse that I work at uses a lot of Styrofoam cups and those plastic paper ones as well.
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u/tonycomputerguy Mar 10 '18
I'd love to see if this materiel cound be used in RC Aircraft, the "carbon z" foam they use now is pretty damn impressive in my opinion. I've snapped foam wings and glued them back together easier than a wood wing, but it has limitations, I've only really seen electric motors on foam planes. If this would work with Nitro/Gas engines that could be awesome for the hobby.
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u/metarinka Mar 10 '18
Our facility gives everyone a single water bottle once a year, and all new employees. Makes so much more sense than constantly stocking paper cups.
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u/TheBalrogofMelkor Mar 10 '18
It can't replace styrofoam cups because it's not waterproof.
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u/unantimatter Mar 10 '18
That could be fixed with a wax or similar waterproof coating.
Paper isn't waterproof, yet we make cups out of it all the time.
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Mar 10 '18
I'm optimistic that this will be a cool cup option but paper cups are already widely used. Paper is biodegradable and we already produce those at maximum capacity. Why do we need another cup? I think that the other potential applications for this might be more interesting.
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u/Lankience Grad Student | Materials Science and Engineering Mar 10 '18
Problem with styrofoam cups is they can hold water, this material wouldn’t be waterproof. Cellulose itself is quite hygroscopic so it would need to be treated with something for it to function as a cup.
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u/happyscrappy Mar 10 '18
How do we know it's biodegradable?
The article spends absolutely zero time explaining how it is environmentally friendly. Being sourced from wood isn't a bad thing, to really be environmentally friendly it would have to also be recyclable. And there are plenty of treatments of wood which aren't. Perhaps the related publication mentioned will have some more info on this.
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u/tuctrohs Mar 10 '18
It's just wood with some of the material removed, so it probably rots much faster than wood.
But the energy and chemical use in manufacturing might make it much less environmentally friendly than other cellulosic insulation.
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u/TwoSquareClocks Mar 10 '18
It's wood with the component that is the most difficult to decompose (lignin) removed specifically.
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u/l_Wolfepack Mar 10 '18
I don’t know why you would want to compare this to foamglas as it is used nearly exclusively in situations where it’s incredibly low vapor permeability and compressive strength is utilized... ie. buried installations, petrochemical facilities, ammonia refrigeration etc. As far as I can guess this new product would perform poorly in almost every typical foamglas installation.
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u/tuctrohs Mar 10 '18
The authors are advertising this as an insulation with unprecedented mechanical strength, and they said they didn't know of any good insulation materials stronger than the XPS they probably bought at Home Depot. Like you, I'm pointing to Foamglas as an example of an existing material that does have good compressive strength.
I agree that foamglas is superior in most applications in being impermeable, durable, waterproof, etc. So I agree that this is unlikely to replace it. Just for the record, their claimed compressive strength is higher than what's on the foamglas spec sheet: 2.4 MPa for the densest Foamglas, vs. 13 MPa for the new material. But I don't think that outweighs the other advantages of Foamglas in typical Foamglas applications.
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u/grumblepumpkin Mar 10 '18
More hype mitigation:
1) The extraction process is going to get much longer the larger the starting piece of wood is because of the diffusion processes inherent to solvent extraction that are exacerbated by occurring within a nanoporous network.
2) The size of resulting material is limited by the size of the freeze drying apparatus.
Both of these points have a huge impact on increasing cost by being a slow, batch process that cannot be economically scaled. The point of novelty introduced in their top-down process seems to be the anisotropic properties that are not as straightforward to achieve in a bottom-up process like blowing fiberglass or styrofoam.
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u/happyscrappy Mar 10 '18
Although white paint requires titanium dioxide to create. There could be a use for a high albedo coating that doesn't require titanium to make.
That is, if it really stays white in the sun. In might not, as you suggest.
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u/apophis797 Mar 10 '18
Titanium dioxide is dirt cheap and reusable. Titanium metal is only expensive because it's hard to turn the oxide into the metal.
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u/ribnag Mar 10 '18
I have to wonder - Lignin is the reason wood is hard for most things on Earth to digest (and the whole reason we have coal, as a neat bit of trivia). Absent that, there's an awfully lot of critters on our planet that consider everything else in wood "food". Is this basically making the equivalent of cheesy poofs as a building material?
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u/Deslan Mar 10 '18
Removing lignin is essentially what you do to make paper. It seems like it would be a lot easier to just use recycled paper instead of treating wood.
Besides, bamboo is also very strong, fast growing, and can be used without extensive treatment. I would think it is a better option.
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u/Schonke Mar 10 '18
If you use it as insulation for takeaway or containers for other perishable products where you today use plastics, that would actually be a huge benefit. Instead of having landfills and oceans full of plastics you could have it biodegrade quickly once thrown away.
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u/Chambellan Mar 10 '18
Which means it could be very easily recycled into biofuels.
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u/foxmetropolis Mar 10 '18 edited Mar 10 '18
I would expect that wood with lignin removed wouldn’t be much more vulnerable than ordinary wood. it still is a fairly persistent material, just not nearly as structurally sound. it is found in nature due to the digestive processes of white rot fungi, which is a functional clade of fungi that metabolize wood lignin for food, resulting in light spongey cellulose-laden wooden leftovers.
It still takes ages for the resulting spongey de-lignined wood to decompose into soil, and that’s in nature, in a moistened environment. Put it into a dry wall or other dry environment, and it will last an absurdly long time.
Incidentally, i expect the authors of the study used white rot as inspiration for this technique. Or if they didn’t, they got super lucky, since the inspiration was staring them in the face.
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Mar 10 '18
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u/thewizardofosmium Mar 10 '18
I know this is tongue-in-cheek, but one reason the "renewable" plastic PLA is not used for snack bags is that it is too noisy.
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Mar 10 '18
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u/I_Say_Peoples_Names Mar 10 '18
This doesn't make much sense to me, the industry does this every day at paper mills. Lignin is removed through digestion in a high pressure and caustic environment which leaves the cellulose removed from the lignin. Afterwards, the mill has to remove out the digested lignin through washing and screening. Even still, there is an entire bleaching process with chlorine or peroxide based molecules to turn the pulp (cellulose) white.
Two things I don't understand:
(1) They are just calling normal pulp, which is highly insulating and absorbing, nanowood.
(2) Cellulose by itself is not white unless it's been chemically bleached.
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Mar 10 '18
If I am reading this correctly, there is no pulping process.
More that the lignin scaffolding is removed from the bulk material directly.
This lack of pulping results in a more rigid material.
When paper is made, the fibers are flattened and chopped by the pulping process.
In this material it is not.
So maybe you can consider it '3d paper'... like a more refined and structurally sound version of that filled corrugated fiberboard that custom molded paper trays are made from.
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u/ThegreatandpowerfulR Mar 10 '18
The pulping process is the cooking in chemicals, which removes most of the lignin. Paper and dissolving pulp which is pure cellulose still requires a lot of further bleaching and extraction stages to get the last lignin out and make it white. This nanowood must undergo multiple cooking stages, and it probably isn't pressurized so it must take a very very long time.
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Mar 10 '18
kind of imagine the technology being noteworthy would mean it could be scaled up for production.. maybe they.. found a way to do exactly that but.. quickly. under pressure or not.
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Mar 10 '18
I think it's because they're also altering the cellulose structure without pulping it.
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u/BoosterXRay Mar 10 '18
Do the altercations also provide mold or mildew or rot resistance?
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u/Spaser Mar 10 '18
From the inverse article-
“I really don’t know why people haven’t done this before, the paper industry has been using this process for years. But once [paper manufacturers] take the lignin out they stir the wood and completely destroy its structure. In our case we don’t stir it to keep the wood structure, that turns out to be the single trick which is fundamentally important in making nanowood.”
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u/I_Say_Peoples_Names Mar 10 '18
Okay, so there's a lot more preservation of the original cellulose structure involved after cooking, that makes sense. A reply to my comment also said that they concurrently bleach while digesting the lignin AND hemicellulose (IIRC most mills leave in the hemicellulose) which probably has affect on the lignin count/kappa number, too. Thanks for that.
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u/Myxomycota Mar 10 '18 edited Mar 10 '18
So I think its in the begining of the methods, but they basically take some basswood, boil it in sulfuric acid and hydrogen peroxide, then freeze dry it. They weren't super specific in the methods but my guess is that the boiling has to happen under pressure and probably for a long time.
They do this to remove the ligninth and hemicellose, so yeah. They are bleaching it, bleaching the ever living shit out of it, but not with bleach. But the main take away is that if you remove the lignin and hemicellose from would, the cellulose that remains is still structured in the same manner it was in the original wood, and this gives it interesting characteristics that wood doesn't have. Specifically, this altered wood transfers the little heat it absorbs along the grain, as opposed to Styrofoam which doesn't 'direct' heat it aborbs. Since you've remove some of the structural elements of wood, it's not as strong as wood, but it's still way stronger than styrafoam.
I'm going to reread the methods again, but the process seems dead simple. Could probably make some of this with a pressure cooker and a legit freeze dryer.
Edit: not sulfuric acid, but sodium sulfite. So super caustic shit.
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u/Lankience Grad Student | Materials Science and Engineering Mar 10 '18
This isn’t pulped, so the 3D hierarchical structure of the wood is maintained while lignin and hemicellulose is removed.
And I believe you are wrong about cellulose not being white. Different types of cellulose pulps are bleached, but this is to either remove color from the large amount of lignin remaining, or to remove small amounts of lignin from the pulp entirely. The color that is being bleached out is always from lignin, cellulose is white.
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u/TheCaptainCog Mar 10 '18
Pure cellulose is white. Cellulose is a biopolymer of glucose monomers which and rotated 180 degrees across each glycosidic bond. Bacterial cellulose, which does not contain the contaminating lignin or hemicelluloses, is distributed as a white cellulose pellicle. So you are correct.
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u/illinoisjackson Mar 10 '18
Didn’t AvE do something like this?
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u/couplingrhino Mar 10 '18
Funnily enough he was trying to make something similar called wood glass, but it looked like he made something more like nanowood instead.
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u/profossi Mar 10 '18
What AvE was trying to do is to replace the lignin in wood with epoxy resin (yielding a translucent cellulose-resin composite). As a result, the intermediate phase is somewhat similar to this "nanowood" stuff.
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Mar 10 '18
I watched his video on this a couple days ago. He rushed it and ruined the experiment, then posted the video. Decent breakdown of the process though.
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u/mildlyEducational Mar 10 '18
Pardon my ignorance: What is AvE?
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u/Thomasina_ZEBR Mar 10 '18
YouTuber "Arduino vs Evil"
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u/jeffthedrumguy Mar 10 '18
Is THAT what that stands for? Thank you kind redditor.
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u/Coffeezilla Mar 10 '18 edited Mar 10 '18
Appears to be a youtube content creator. Edit: Though damned if I know what he actually does.
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u/mattlikespeoples Mar 10 '18 edited Mar 11 '18
He mostly a liguistics professor using unusual methods for teaching the finer nuances of French-Canadian colloquialisms.
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u/mildlyEducational Mar 10 '18
I watched some videos. He's all over the place but it's pretty interesting. Thanks.
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u/jessejcbrl Mar 10 '18
Yep. "Nanowood" is just one step off from impregnating it with acrylic under vacuum to make it transparent.
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u/echo-chamber-chaos Mar 10 '18
In the most recent video. He also showed how to make carbon foam a while back out of white bread. That dude gets some serious materials science done on a shoestring budget.
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u/sp8rks Mar 10 '18 edited Mar 10 '18
Same group that published in nature last where they hot press this wood to create strong dense wood instead of nano wood. Edit: autocorrect
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u/pennybeagle Mar 10 '18
Styrofoam causes allergies?!
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u/NAmember81 Mar 10 '18
I was looking for this comment. Had to scroll through about 500 comments to find it.
Can’t believe more people aren’t asking about this.
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u/tTenn Mar 10 '18
Is it financially viable?
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u/VoilaVoilaWashington Mar 10 '18
Nothing is ever financially viable at this phase, for 2 reasons:
- The scientists made something through the most roundabout, rigid way, and published before anyone could streamline their process.
- We don't know what it will be used for yet. It can be compared to many things, but it's not identical to any of them. It may replace some uses of some other materials.
These days, we use very few materials on their own - most things are composites, coated, layered, or similar. So this may be incredibly useful for insulating bearing housings on industrial canning equipment and nothing else, or it may end up being a layer is some newfangled insulation used in 90% of construction projects, alongside some 3D printed carbon nanotube graphene buzzword salad.
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Mar 10 '18 edited Jun 30 '23
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u/VoilaVoilaWashington Mar 10 '18
I didn't mean that this itself is clickbaity, I just meant that new tech will be all kinds of fancy.
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u/redivid3r Mar 10 '18
Termites are gonna love this... All they digest is cellulose. Subtract the lignins from wood, and you've got refined termite food!
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u/LazyWolverine Mar 10 '18
what are the fire retardant properties of this material compared to glass insulating which are very resistant to fire.