Transparent Wood Composites [1] "are novel wood materials which have up to 90% transparency and higher mechanical properties than wood itself". This latest paper Solar-assisted fabrication of large-scale, patternable transparent wood [2] describes a technique that brings this material one step closer to production scale:
> Here, we report a method to produce optically transparent wood by modifying the wood’s lignin structure using a solar-assisted chemical brushing approach. This method preserves most of the lignin to act as a binder, providing a robust wood scaffold for polymer infiltration while greatly reducing the chemical and energy consumption as well as processing time. The obtained transparent wood (~1 mm in thickness) demonstrates a high transmittance (>90%), high haze (>60%), and excellent light-guiding effect over visible wavelength. Furthermore, we can achieve diverse patterns directly on wood surfaces using this approach, which endows transparent wood with excellent patternability. Combining its efficient, patternable, and scalable production, this transparent wood is a promising candidate for applications in energy-efficient buildings.
This same group has previously described A Clear, Strong, and Thermally Insulated Transparent Wood for Energy Efficient Windows [3].
I’m really disappointed with this narrative that natural fibres infused with chemicals are somehow still natural.
“Bamboo fibre” bowls made with plastic for a recent trend: Not just not biodegradable as the name suggests, but also not recyclable.
Like “vegan leather” (made from processed crude oil), these terms only seem to take us away from the products that we are actually looking for when something says “natural”.
I don’t understand what “natural” has to do with the article. The article mentions a new material that is transparent and has better insulating properties and makes no claim about being natural
Is it honest to still call their product wood? That's the question, calling it wood seems to misappropriate/inherit the assumed values of wood to their product. "Transparent wood" feels better than whatever other title they likely could come up with.
Thankfully we have had similar naming laws around the “wood” you mention. They are not perfect, but they are enough if you know what you’re looking for.
I had a discussion with a maker of hand crafted canoes about materials. He was surprised that his cedar-strip [1] canoes were lighter than the equivalent kevlar (which is well known as being lighter than fiberglass but more expensive and harder to repair). The key factor accounting for the weight difference was the amount of epoxy absorbed by each material.
Ultimately this is about material science and the various trade-offs inherent in each choice. Cedar-strip canoes have a highly valued aesthetic quality but "wood-strengthened epoxy" is an accurate description of the material; the epoxy, however, is not the distinguishing feature of cedar-strip, kevlar, nor fiberglass canoes.
Like all evolving innovations, "transparent wood" seems to be searching for its killer application and I don't expect the name used by researchers to continue if/when it finds product-market fit.
> Scientists develop transparent wood that is stronger and lighter than glass
That’s the article title, and it’s very easy to argue that they are looking to misappropriate the “wood = natural (and renewable) resource” properties. The current HN title from the paper even goes a step further by pairing it with “Solar-assisted fabrication“.
Wood has fantastic mechanical properties. It's also renewable to produce. I would gladly take a piece of half renewable transparent sheet vs a 100% petroleum acrylic sheet.
The normal bleaching process is quite energy intensive, so that is also a win.
No. If it's not 100% all natural it's green-washing.
Eh? Firstly there are plenty of “natural” or organic epoxies that can decompose.
Secondly that’s not the point.
Glass is a very energy consuming process, it’s heavy and a PITA to transport and it’s also a very good heat conductor which means for insulation you need to use multiple glass sheets with an air barrier.
This material is lighter, it’s a way to sequester carbon, it seems to be less energy intensive both to produce and transport and provides better insulation from the get go.
If this can be developed as a drop in replacement for window glass alone it can likely save a lot of energy both in the manufacturing and then in the heating of homes.
Even if it’s not biodegradable not everything needs to be, most glass isn’t recycled either, and it’s not like glass recycling is a particularly cheap process.
The glass from your glass recycling bin is usually just crushed and added as a filler to other materials not melted to make new glass.
(plastics not generally being recycled aside since that’s a much heavier topic) I’d honestly disagree that it’s better to embed plant material in plastics or other non-degradable material.
At least a fully plastic cup made of a single plastic could theoretically be recycled easily. When you embed it now has to have specific processes to deal with that before being recycled, and those processes might have to be specific to that one product (or at worst: the process becomes “burn out all the impurities, throw the smoke in the air”)
It is relatively straightforward to dissolve cellulose. So adding it to epoxy does not necessary make it harder to recycle. I can speculate that with the right chemistry it can be more energy efficient to recycle the mixture compared with pure plastic.
And to my point: You’re talking about a potential specific process for that one specific product. What if the manufacturer uses and emulsifier or infuses the cellulose with additional chemicals?
Yeah, I read an article about this last night. This isn't fundamentally different from how fiberglass works: a bunch of fibers embedded in a bunch of epoxy. That the fibers were at one point a tree doesn't mean I'd put this material in my wood stove on a cold day in February.
I have a similar grip with "plant-based meats" - no, it's not meat and doesn't accurately mimic meat either; and if you want to go a layer deeper, meat is already plant-based due to the animals eating plants which then get concentrated down into dense nutrients and calories, and if talking about high fat red meat, then in the exact proportions our body and brain needs -which makes sense since we're animals too.
> "meat is already plant-based due to the animals eating plants which then get concentrated down into dense nutrients and calories"
Sure. But it's much more environmentally efficient in terms of water use, carbon emissions, etc if we can make sufficiently tasty and nutritious foods directly from plants rather than going through the inefficient animal step. Many people also have ethical objections to consuming animals.
Please watch the documentary Sacred Cow which will counter your "more environmentally efficient" claim - as it's taking into account the holistic view of the full system of environmental processes.
It would be ‘meat like’ but it doesn’t make much sense for the marketing. And meat also refers to the edible part of fruits or something consistent. I’d give it a pass as its not really deceiving advertising.
Less so with those, as your examples are primarily a single ingredient - though most almond milk available now is full of junk other than almomd. And in those cases they're not trying to mimic other products or claim it's anywhere near equivalent nutritional and other values/quality of non-factory farmed meat. Maybe I just need time for my brain to unravel my definition of meat but there's a mob that tries to falsely claim equivalence.
> 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
so they replaced the wood with epoxy, and called it wood. Like a car where you replace everything but the VIN so it keeps it's identity?
It sounds more like the process that's used with carbon fiber - epoxy is poured around the carbon fiber cloth and the end result is something with properties of both.
The article is scant on details so it may still be bunk, but I still think it sounds like an interesting application.
As you can see from the video it is basically impossible to scale this process to large pieces of wood. Discussions about replacing windows with this are pretty pointless I think.
This video is based on a different paper from 4 years earlier and it uses a different technique.
If you read the new paper, one of the main properties of the new technique is that it does not affect the wood lignin, so that the final transparent wood has the same properties, almost, as the original wood. In this video you linked to, the techique involves completely removing the wood lignin (see 4:08). Clearly not the same thing.
Another huge difference: in this video, the wood is dropped into a boiling chemical solution for 12 hours. In the new paper, the solution is brushed onto the wood at room temperature, then the wood is left exposed to UV light (which can come from natural Sun light) for just one hour.
The video uses boiling, distilled water to wash the wood (for only around 15 minutes), then hydrogen peroxide (in an awkard attempt at removing the lignin left) after the chemmical treatment of the wood, while this paper just mentions using ethanol (5 hours immersion) to remove just the chemical solution from the previous step.
The video mentions that after all this, the paper it's based on says they still need to boil the wood into a 8% peroxide solution (the video author decides to use much less, though, at 3% due to "foaming" problems) until the wood turned white, after which they use ethanol to remove the chemicals. In the new paper, this step doesn't exist at all. The UV light is enough to achieve that and the wood had already been washed with ethanol.
Only the last step, using vacuum to infiltrate epoxy into the wood, seems to be similar between the two different papers (though the author of the video did not have a very good techique to do that... both papers are quite lean on details, so the author of the video can't be blamed here).
I mention all this because you and other people in this thread are choosing to dismiss this new paper based on a video about a completely different paper, using a totally different methodology, which shows that you're either trying to intentionally present misinformation to HN readers, or that you didn't bother to read the new paper at all and just assumed nothing new in it.
Please avoid such behaviour in public forums, the last thing we need is more disinformation and lack of depth in our dicussions.
some notable addition, H2O2 itself is a great bleaching agent but exposing it to UV creates the Ozone gas which is also used as bleaching agent for wood pulp in industries. so, the process accelerates in its own. this process could be further accelerated if H2O2 soaked/brushed wood is placed in transparent airtight container(glass aquarium with sealed lid) for sunlight UV exposure,this process increases the concentration ozone and can ultimately give better result.
Other notable thing is the thickness is 1mm only which reduces the required penetration depth of epoxy to only 0.5mm if applied from both side separately. In the video they used 3mm which is three times more thick. The 1mm thickness itself also a limitation for wide array of applications, further research to increase effectively increase the required thickness of wood will make it viable for bigger market.
btw,I really liked the newer process which uses the already well-known chemistry and give better results.
I think nay saying needs to be seriously curtailed. It's far too effective for way too little actual content. This is a great example of a trend that's infecting and harming HN discussions.
We need more people to read up on a topic and have an earnest conversation around it. Gut reactions or memories from years gone by of old techniques aren't constructive and are actively destructive.
these are similar approaches but different from a cursory glance, the nile red video is based on a paper from 2016, this was published in 2021 and they are treating 1m lengths of wood and have a 10cm transparent piece that looks far more promising than the 2016 version, or Nile Reds
There's a lot of holes in this article. They made a one millimeter thick sheet of organic matter transparent by bleaching it and then filling it with clear epoxy. None of that indicates a utility for building materials. You could do that to almost anything organic, from a sheet of intestinal lining to a seaweed nori roll. To beat glass and plastic it has to scale. Call me jaded but I think if these guys could produce a transparent 2x4 they'd have shown it off.
If they use an epoxy with the same refractive index as celllose and manage to totally eliminate any gaps/air they will get closer to glass, but I feel it will stilll be a little foggy. They have been playing at this for decades because cellulose is the cheapest fiber. You can use a solution of cellulose(Viscose https://en.wikipedia.org/wiki/Rayon) that you spin into fine monofilaments to immerse in a similar epoxy pane for the same effect,
The process is more involved than it seems at first, nasty toluene is required and only mentioned once in the methods section.
The chemical treatment is a bit different, but I would expect similar results and difficulties as NileRed found when following the previous method from the same research group in 2016: https://onlinelibrary.wiley.com/doi/full/10.1002/adma.201600...
Yes, the material described there is not wood but an epoxy-based composite reinforced with wood fibers instead of glass fibers, like in PCBs, or carbon fibers, like in high-strength composites.
The only remarkable thing is that they have succeeded to match so well the refractive index of the epoxy resin to that of cellulose and bleached lignin, so that the composite is a clear transparent material instead of being just diffuse translucent, like most composites.
This might make this composite a better choice than polycarbonate or acrylic glass in many applications.
They should have given a comparison between the properties of the new transparent material and those of polycarbonate, because that is their main target market, not glass. Anorganic glass cannot be replaced by polymers in many applications, due to requirements for chemical resistance or high temperature resistance.
Sand mining is causing environmental degradation around the world, to river beds, agricultural lands, etc. Taking that out of the equation could be a net benefit. Especially if it's at least as permanent as glass.
Sand isn’t a uniform thing, for glass you can use wind blown sand from deserts because it’s melted. Which in practical terms is an unlimited resource as Si makes up 28% of the earths crust which is only behind Oxygen.
But, for extending beaches and most other uses you want textured sand that clumps together. As such people don’t mine river beds for large scale glassmaking as that sand is more valuable.
If it only diverts mining from near-lifeless deserts, that might be more acceptable. All deserts do have life though.
But what's the impact of cutting down trees + mining for some fraction of petroleum vs mining for glass? I would guess that it requires a rigorous and impartial analysis of the environmental impact.
There is very little danger of any world's deserts becoming sandless (or even making a dent in the amount of sand) due to the needs of glass manufacture.
I'm not even sure I'd call it a "danger." The Sahara creeping south is a danger. If we could make a dent in the amount of sand, it'd be a pretty amazing thing.
I was hinting that deserts aren't devoid of life, so it's still destroying some environment and habitat, even if it's one that humans have little value for. But, OTOH, felling trees is likely much worse.
If it proves to be more durable than glass, requires less energy, and also offsets demand for mining, it could be a net gain. I don't have understanding of the supply chain, and the environmental impacts of glass manufacturing to know.
Recycling could be difficult (once again, I don't have the domain knowledge), but that's only an issue if it needs replacing.
Of you could toss the carbon you don't want into old coal mines (or just land fill) - why would you burn it and cause more global warming, we should be tossing our used paper into landfill, recycling it reduces the demand for growing more trees (and fixing more CO2
windows glass isn't easily recyclable either. it can be repurposed...
> However, while window glass may not be recycled easily, there are many options for keeping it out of the landfill. For example, it can be melted and re-manufactured into fiberglass, incorporated into asphalt, and even combined into reflective yellow and white road paints. Broken glass can be combined with concrete to create terrazzo flooring and countertops. Some companies even use old glass for landscaping materials and other decorative applications.
Glass doesn't decompose, it gets eventually pulverized back into sand (naturally or manually).
The issue with glass though isn't how it's handled once we're done with it. The issue with glass is energy loss. We lose a huge amount of energy to the windows in our home, and it might be worth it to make wooden window panels if it means that we end up consuming less energy HVACing our homes. Especially since house windows can be expected to last for decades, which amortizes their disposal cost nicely.
The R value of wood is not great [1] and would depend on the type of wood used and thickness. Double pane windows tend to have an R value of 1-2, which increases if filled with a gas [2]. Your hypothesis that we'd curb more energy loss is a bit misplaced without more nuance.
Double glazed windows might be more efficient, but that's irrelevant if you simply don't use double-glazed windows. I know single-glazed is quite common in Australia, apparently because there's no local factory for mass producing double-glazed and there's no market base right now because it's so expensive because it's imported, so nobody wants to take the risk.
Double glazed has been standard for at least 20 years if not 30 here in the Netherlands. It is primarily intended to keep warmth inside during colder periods. Newer projects tend to have triple or quadruple glazed glass with all kind of coatings. To keep the heat out in summer an infrared blocking coating is applied. In office buildings here it is more efficiënt to heat a bit more in winter due to loss of IR than to cool extra in summer.
I’m not sure that’s true. We had gas filled double glazed windows made for us in Eltham, an outer suburb of Melbourne, during a renovation about 6 years ago. We replaced all the single paned glass with double panes. And we were on the edge of the Yarra valley, not particularly close to the city. So my experience doesn’t match this at all.
It's because it isn't true. There's a number of outfits and pretty much every new apartment building has double glazing. I've lived in 4 properties since moving to this country, 2 with and 2 without. Of those with, 1 new and 1 probably last renovated 15 years ago.
That is surprising given the amount of AC you use. I lived for a few years in a similar climate to Melbourne and double glazing made a huge difference in the Summer.
In fact, triple pane windows are mandatory for all new construction in the EU as of this year[1]. I think double pane windows have been mandatory for years. Modern triple pane windows have less heat loss than the walls of most buildings built a couple of decades ago.
And as the article mentions, they used a marine epoxy. I haven't met a marine epoxy (or poly resin) yet that doesn't have to be coated to avoid UV damage.
A plastic window would need to be quite thick to be as rigid as a glass window. A plastic window would also scratch more readily, and it would likely degrade in the sun (become translucent rather than transparent). It’s not obvious to me that this wooden material somehow wouldn’t have the same problems.
Plastic is more expensive, easily scratchable, and isn't as rigid as glass. Glass makes a lot more sense unless there is a very high risk of it shattering.
The last time (before the pandemic even) I looked at glass and acrylic/polycarbonate sheets for a project, the glass was cheaper for a similar size. Maybe there are other plastics out there that are cheaper, but I'm not sure that they are suited for similar use. If they are suited to this type of use and are cheaper, then someone can make a good fortune if with the right marketing.
What do you mean? From a consumer perspective dealing with sheets, one requires dimensions for a project, not weight. Whether measured by weight or by dimensions, the glass was cheaper.
Also plastics scratch more easily. Something like plexy glass also breaks pretty easily similar to normal glass. Poly carbonate is much stronger but also quite expensive even when compared to normal glass. It also scratches easily.
I heard about this a few weeks ago. I googled how to recycle (or dispose of) epoxy resin and haven't found anything. That is kind of disappointing. Some companies are trying to develop an epoxy resin formula that can be recycled but that's just a tiny niche of the market.
I don't see this going anywhere unless that issue has been resolved for good. Does anyone know more about recycling epoxy?
It would seem not too difficult to reuse, though. I reuse a fair bit of regular lumber, as for example when I disassembled the old falling-down back porch and made several indoor benches out of it. I would think epoxy-infused wood might be less prone to rot, and so even more reusable.
Wonder how long until someone makes a transparent glider or drone with it? :)
--
Hmmm, some of the text under the photos in the article are extremely misleading:
Researchers demonstrated after brushing a coat of hydrogen
peroxide on the opaque wood material, and exposing it to
one hour of sunlight, it turns transparent.
No mention of epoxy there, though it's literally a key ingredient as mentioned in the full text.
I think the material itself does literally become transparent. It's just that the rough surface makes it look white (see: https://en.wikipedia.org/wiki/Frosted_glass). Just like you can make frosted glass look transparent by e.g. putting some clear scotch tape over the surface (https://i.imgur.com/GZLOfbR.jpg), you can restore the transparency of the wood by filling the gaps with resin.
It seems to go from "You merely brush h2o2 and leave it in the sun for an hour" to additional steps involving a lye solution at the start and a vacuum chamber for another hour and a half at the end.
I still think it is interesting and probably useful. But it starts off understating the actual effort involved.
Can you please read the article before posting? The thickness is mentioned in the article and also the fact that the technique works for numerous species of wood.
One advantage of glass in windows is that, when broken, it will make for a noisy mess. I'd say this partly discourages break-ins to vehicles and homes.
If windows were made of something that could be splintered and more quietly pulled apart, I'm not sure it be as useful for the typical glass windows and doors we know.
For housing this might be good, diy a window. Or even prototype labs, glass making looks pretty hard without a factory. But for mass produced consumer items like food and drink jars ect I think this is a bad idea as it will just add to urban waste and recycling problems.
But by making wood transparent, would it not be even more detrimental to the environment? Plus at least glass is made of silica which we have no real shortage of and it can be recycled as well.
In the spirit of "best thing we can do with carbon is bury it", this could be great for the environment. Assumptions: less energy used for production than melting glass, easier process and shorter transport distances, recycling glass takes more energy than burying / decomposing the wood, we get even more commercial reasons for planting trees.
The problems could be in how long that "wood-glass" lasts. Will you see cracks soon? Will any insects start drilling your windows?
This is wood soaked in epoxy. The epoxy should provide plenty of protection (note that lots of houses are made of regular wood, so I don't think this is much of a problem anyway).
> note that lots of houses are made of regular wood
Yes, but that's why in certain areas you need to do termite inspections because the treated wood doesn't provide 100% protection. Also the wooden parts are normally protected by other materials to not be exposed to rain and rot - in this one the epoxy layer would likely do that, but still, it depends on good coverage/protection.
That's not what the article says. There is a shortage of sand for cement, which needs rough, sharp, unweathered sand. For glass there is no shortage at all.
Glass is a poor insulator. They're claiming transparent wood would have better insulating properties, retaining heat inside buildings. A lot of energy is lost through windows.
It’s just used to bleach the wood, like some people do to lighten their hair. The sunlight accelerates the oxidation process. So the hydrogen peroxide does break down but that’s the intention. It removes the pigment from the wood fiber, the epoxy fills in gaps to allow the translucency.
> Here, we report a method to produce optically transparent wood by modifying the wood’s lignin structure using a solar-assisted chemical brushing approach. This method preserves most of the lignin to act as a binder, providing a robust wood scaffold for polymer infiltration while greatly reducing the chemical and energy consumption as well as processing time. The obtained transparent wood (~1 mm in thickness) demonstrates a high transmittance (>90%), high haze (>60%), and excellent light-guiding effect over visible wavelength. Furthermore, we can achieve diverse patterns directly on wood surfaces using this approach, which endows transparent wood with excellent patternability. Combining its efficient, patternable, and scalable production, this transparent wood is a promising candidate for applications in energy-efficient buildings.
This same group has previously described A Clear, Strong, and Thermally Insulated Transparent Wood for Energy Efficient Windows [3].
[1] https://en.wikipedia.org/wiki/Transparent_wood_composites
[2] https://advances.sciencemag.org/content/7/5/eabd7342
[3] https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.2019075...