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Hardened wood as a renewable alternative to steel and plastic

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Re: Hardened wood as a renewable alternative to steel and plastic

#51

Post by panzagl »

hammock wrote: post #25

Here is a non-paywalled description of the process. https://www.popularmechanics.com/science/environment/a167588... >Lignin is what makes wood rigid and brown. Somewhat counterintuitively, Hu and his team removed the wood's lignin polymers in order to make their wood even stronger. >The lingin removal allowed the team to compress the wood under a mild heat of around 150 degrees Fahrenheit. Without the lignin binding…

Are the long term effects any less detrimental than other polymerized materials, or is this basically another way to make plastic?

Re: Hardened wood as a renewable alternative to steel and plastic

#52

Post by clairity »

shawn-butler wrote: post #46
clairity wrote: post #34

Earlier quoted context omitted.

from what i remember, it’s up to 6 stories in some parts of the country. i think it’s other aspects of the zoning and/or building code that tends to limit it to 3 stories—often podium style, with a concrete bunker foundation for cars with 3 stick-built stories on top. for the record, i dislike this style because it reserves the most valuable square footage—the ground floor—to cars. the cars should go underground, all…

This is (was?) the largest mass timber structure in the US. I think it is 7 stories. https://structurecraft.com/projects/t3-minneapolis

yah, that’s an awesome building, especially the exposed beam interior. it’s interesting that they used nail-laminated timber, which is just regular lumber close-packed and nailed together with plywood, in place of concrete floors/ceilings. according to the site, they’ve moved on to using dowels instead of nails for this.

Re: Hardened wood as a renewable alternative to steel and plastic

#53

Post by dirtyid »

account_b wrote: post #29

As far as I know, the Earth's surface cannot meet humanity's current need for hydrocarbons, polymers or building materials. Biomass production is limited by sun energy and most importantly phosphorus and nitrogen cycles. Even hundred of years ago, people were already exhausting regenerative capacities and back then there were only around half a billion humans living on all this planet. Petrol chemistry and mineral ex…

Do you have any recommended readings or search terms to explore this subject?

Re: Hardened wood as a renewable alternative to steel and plastic

#54

Post by meepmorp »

oliwarner wrote: post #41

The graph in that composite diagram is really bothering me. Their "hardened wood" product is 23 times harder than "natural" basswood. When dried, basswood (aka lime) is an extremely soft hardwood. It's very popular with novice turners and hand carvers. When green (natural?) you can carve it with a stone. Species matters. Lignum vitae is 20 times harder than basswood.

I think the point of using basswood as a reference is to demonstrate the effectiveness of the hardening process by using a very soft wood. Separately, basswood is fairly quick growing, making it a decent candidate for commercialization of the whole technology.

Re: Hardened wood as a renewable alternative to steel and plastic

#55

Post by account_b »

jnmandal wrote: post #36
account_b wrote: post #29

As far as I know, the Earth's surface cannot meet humanity's current need for hydrocarbons, polymers or building materials. Biomass production is limited by sun energy and most importantly phosphorus and nitrogen cycles. Even hundred of years ago, people were already exhausting regenerative capacities and back then there were only around half a billion humans living on all this planet. Petrol chemistry and mineral ex…

This is pretty clear to me too. We survive on stored energy borrowed from the past. Energy and growth are basically finite. We do need to cut down. We also need to develop tech (weather technique or technology) to reconstitute waste and refuse into the inputs for our food, buildings, transportation, etc.

> We survive on stored energy borrowed from the past.

It's worse than that: We fully rely on borrowed time!

Natural geological cycles to restore surface phosphorus span many thousands of years. Our current agriculture (food production) critically depends on mineral phosphorus, which may be exhausted in just four or five decades. And we retain none of that, but flush our soils into the oceans (partially through the toilet, literally). No phosphorus, no food. I wish everybody knew about peak phosphorus. (It's also a geopolitical near future issue as almost all phosphate rock is located in Morocco...)

> We also need to develop tech (weather technique or technology) to reconstitute waste and refuse into the inputs for our food, buildings, transportation, etc.

Yes! We also need to collect and recycle human and livestock feces and urine to prevent mineral loss. Those cannot leak from the ecosystems anymore - madness!

Honestly, I think it's possible humanity will barely not make it, comically, because no one wants to lobby for collecting people's shit, while everything else goes full Star Trek.

Re: Hardened wood as a renewable alternative to steel and plastic

#56

Post by wrycoder »

svachalek wrote: post #48
jonpurdy wrote: post #24

Earlier quoted context omitted.

Curious about your opinion on bamboo products. I assume you're referring to modern bamboo desks, shelves, and other items that are made from Chinese bamboo and made in China. They typically slice the bamboo grass pieces into ~8 sections, then use planing machines to create planks※. These are then pressed and glued together to make products. These products are then shipped overseas using the same methods as other prod…

The usual complaint I see against bamboo products is that they use hard bamboo that grows like trees, but promote a sustainable image based on the idea of soft bamboo that grows like grass. I haven't heard it's less sustainable than wood, just not any more sustainable.

Kg of wood per hectare-yr would be a good measure of how much useful wood is created, and also how much carbon is locked up in it.

Re: Hardened wood as a renewable alternative to steel and plastic

#57

Post by chrisweekly »

wrycoder wrote: post #56
svachalek wrote: post #48

Earlier quoted context omitted.

The usual complaint I see against bamboo products is that they use hard bamboo that grows like trees, but promote a sustainable image based on the idea of soft bamboo that grows like grass. I haven't heard it's less sustainable than wood, just not any more sustainable.

Kg of wood per hectare-yr would be a good measure of how much useful wood is created, and also how much carbon is locked up in it.

Time is a critical factor (ie, the "yr" in your metric). Bamboo grows _incredibly_ fast.

Re: Hardened wood as a renewable alternative to steel and plastic

#58

Post by OldHand2018 »

raman162 wrote: post #11

I wonder how fire resistant hardened wood is. I can imagine cities like Chicago having a hard time to use wood in commercial buildings with history launch as "The Great Chicago Fire"[0] [0]: https://en.wikipedia.org/wiki/Great_Chicago_Fire

Chicago allows mass timber buildings up to 6 stories, although a developer has proposed an 80-story mass timber building. So that guy may do all the work to open the door.

Re: Hardened wood as a renewable alternative to steel and plastic

#59

Post by agumonkey »

sfink wrote: post #12

I've been intrigued for a while about various modified wood technologies (eg hardened wood, transparent wood), but I'm always disappointed because it usually ends up just being a minor support structure for a very non-wood material (generally epoxy). This one shows a compression step, so maybe it's different, but I'd really like more info on whether this is actually renewable or sustainable in any interesting sense.…

I, too, would like to see "green" engineering. How to nicely tap in biosphere / organic material to make whatever we need.

One old trick was hemp plastic.. I'm not sure what was bad about it since nobody tried it again since Ford made a prototype car body with it.

Re: Hardened wood as a renewable alternative to steel and plastic

#60

Post by nick238 »

fluxflexer wrote: post #33

The most interesting thing is the Force/Displacement curve. It shows some plastic deformation even after the breaking point, which is unusual for „hard“ Materials. May this just be some gloryfied Epoxy with wood as filler?

That stress/strain curve in the Cell Matter "Graphical Abstract" is garbage past the point of peak stress. If it's tested in their double shear jig as shown, once it displaces significantly (> radius of the nail) the force is more the pull-out force, basically just the friction between the hole and the nail surface. Or, the nail might just be digging an oblong hole in the shear jig. It's maybe interesting, but a regular stress/strain setup is better to lead with.

The Nature article has some normal stress/strain curves which show brittle failure https://www.nature.com/articles/nature25476/figures/6

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