Why wood pulp is world's new wonder material | Hacker News Reader

Why wood pulp is world's new wonder material

newscientist.com

123 pointswmeredith52 comments

This brief article about current uses of wood pulp reminded me of something I read in a book back in the 1970s about a proposal to build an aircraft carrier during World War II (when there was a shortage of steel) out of a mixture of wood pulp and water ice. That material was called "pykrete," after the name of its inventor, Geoffrey Pyke. The shortage of steel was alleviated, and plenty of aircraft carriers constructed of conventional steel, before this idea was implemented. In actual use, such a ship would have had to have been continuously refrigerated, perhaps a greater drain on scarce materials than building a ship out of steel.

Sure enough, there is a Wikipedia article about the material,

http://en.wikipedia.org/wiki/Pykrete

which reports that the Discovery Channel popular science program Mythbusters made ship models to test out the idea.

Wikipedia

http://en.wikipedia.org/wiki/Project_Habakkuk

and the Royal Naval Museum

http://www.royalnavalmuseum.org/info_sheets_Habbakkuk.htm

have websites about the frozen aircraft carrier project that relate more details, citing sources other than the book I read decades ago.

AFTER EDIT: I think the book I read about this plan was Of Spies and Strategems by Stanley Lovell,

http://www.amazon.com/Spies-Stratagems-Stanley-Lovell/dp/B00...

although a Google Books search doesn't show the keyword I'm looking for in that book.

That's really fascinating. The boat sounds almost like a mobile version of the huge wall of ice in Game of Thrones. I could see this used to construct space stations and vehicles, to be used where the vacuum of space prevented thawing.

Vacuum doesn't prevent thawing. Vacuum is an insulator against mechanical heat transfer, but it doesn't do anything against radiative heat transfer. Better not bring that pykrete hull anywhere closer to the Sun than, say, Mars.

Also, cellulose is harder to find in space than carbon, iron or aluminum, currently.

>it doesn't do anything against radiative heat transfer

That's easy: put Multi-layer insulation between you and the sun, and install radiators on the shaded side.

http://en.wikipedia.org/wiki/Multi-layer_insulation

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/1971001...

If I recall my science correctly water ice would sublimate in the vacuum of space: http://askville.amazon.com/water-evaporate-vacuum/AnswerView...

In fact, this is pretty much what constitutes a comet's tail.

I remember reading this many years ago. I don't think it is mentioned in the wikipedia article but a further benefit of pykrete was that it would make an aircraft carrier almost immune to torpedo attacks. I didn't see any backup to this but I seem to remember that the aircraft carrier would have a hull of pykrete 14 foot thick, which judging by the bullet tests mention in the article, might have made it exceptionally strong.

I am going on memory on this so happy for someone to correct me.

This sounds unlikely. From what I understand, torpedoes do most of their damage by causing hull flexion of the target ship by exploding underneath rather than punching a hole in the hull itself. An incredibly heavy, inflexible hull seems like it would be easier to crack as opposed to some material that has the ability to bend and absorb shock.

I'm not an expert either so hopefully one of our naval folks will come in and clear it up.

This is true of modern torpedoes, but was not true of WWII vintage torpedoes, which generally smacked into the side of the hull and blew up.

Ahh, thanks for the clarification.

http://en.wikipedia.org/wiki/MythBusters_%282009_season%29#P...

I can't find footage, but Mythbusters had a pretty impressive episode where they tested various formulations of pykrete. Jamie's newspaper-based one seemed to be the strongest. A smallish piece of it held a pile of lead, plus Adam's entire weight, while he smacked it with a hammer repeatedly. They built a little boat out of it which disintegrated pretty quickly. The idea that you could build an aircraft carrier was deemed "plausible but ludicrous". http://mythbustersresults.com/alaska-special-2

I would consider "plausible" and "ludicrous" to be mutually exclusive.

"plausible but ludicrous" can be parsed as "probable [that it would work] but ridiculous"

Militaries have a way of combining them. For example: "normal" aircraft carriers.

There are many things that are possible, but never the optimum solution to any real engineering problem. Mythbusters has a long track record with that sort of thing, probably most notably their functional lead balloon.

You have to remember that surface area increases with the SQUARE of size, but volume by the CUBE. So scale it up by a factor of 10 and you have 100x the surface and 1000x the volume, so it will melt much slower.

Scale it up by ANOTHER factor of 10, and it'll melt another factor of 10 slower, and possibly more. Building-size blocks of ice take months to melt, even in warm temps.

That helps if your aircraft carrier is a solid block...

It applies regardless of scale. The proposal had internal refrigeration, and air is a very poor conductor of heat - most of the heat transfer would occur with the water, not the air, even if the air was 10-20 degrees warmer, maybe more.

Here are some clips from the episode:

http://www.youtube.com/watch?v=UMKis4FPykw

http://www.youtube.com/watch?v=uQO4FDuW3PI

While they didn't build battleships out of Pykrete they did build fuel tanks out of laminated paper and plastic. (An early form of fibre glass, using paper instead of glass.)

(http://www.ww2aircraft.net/forum/other-mechanical-systems-te...)

(http://home.earthlink.net/~charlesfelton/id19.html)

Anyone who has been around a university physics lab will easily recognize linen (as well as paper) phenolics which are typically used as insulators and occasionally for mechanical parts. They used to be pretty popular for gaskets as well.

In general, paper based phenolics were used for tons of things, and if you have anything around that looks like hard plastic that was made before the 70s you've probably encountered it as well (buttons, knobs, etc...). The trade name Bakelite was a general term to denote a paper/linen/cotton based thermoplastics.

http://en.wikipedia.org/wiki/Bakelite

>it is made from a tightly packed array of needle-like crystals which have a strength-to-weight ratio that is eight times better than stainless steel.

That's a pretty useless thing to say. What kind of strength? Tensile? Shear? Yield?

Maybe this figure is buried somewhere in the paper they linked to, but not in any easy to find place.

Looks like they're probably talking about Tensile strength. (http://www.celluforce.com/en/product_properties.php)

Does that put us in space elevator territory?

According to this(http://www.spaceelevatorblog.com/?p=1125), no not yet.

No, at the end of the article they specifically say that they had previously incorrectly said it was tensile strength.

tl;dr: US Forestry Service: We have too many trees ! How can we sell more of them in a declining building market?

The US Forestry service (certainly by Bill Bryson) is regarded as in thrall with loggers (builds roads for access to heavy equipment, sells trees at a loss acting as a subsidy provider etc.)

So the idea that the great new industry, that involves chopping down trees, should be owned by US forestry service, does not inspire confidence.

   The $1.7 million factory, which is owned by the US 
   Forest Service,

Who remembers the Friends episode where Courtney-Cox was asked to come up with some tasty way to make cakes with fish-chocolate?

Probably good news for Canada too as we export a lot of trees to the US.

Canada is at the forefront here. Technology to mass produce NCC was developed by Domtar, and the largest plant is based in Windsor Quebec.

Apparently, the Indian government is funding research in producing nanocellulose out of bamboo:

http://icfre.gov.in/UserFiles/File/Projects/Thurst-Areas/lig...

I am also highly interested in:

  (1) Can nanocellulose or microfibrillated cellulose be made from recycled cardboard, and other forms of packaging we use to transport goods?

  (2) If (1), then can it be made in a machine the size of a Makerbot / Recyclebot?

  (3) If (2), can this material be extruded in a Makerbot-like device (computer controlled, cheap enough for makers < $2000)

I'm kind of curious if this high tech paper can be folded like origami into interesting transparent and super strong creations?

Maybe?

I'm more interested in reducing the numbers of trees chopped down for packaging. I've been recently more conscious of how much package gets put around objects when I get the things I order from Amazon. Further, if these could be done cheaper or faster than pre-made packaging, you could print the package around the object rather than hiring humans to package it up.

It's not just corrugated cardboard. There's also bubble wraps, and all the plastic packaging we use. And just as importantly: how easy is this stuff to recycle? Is it possible to feed excess back into a machine that chops it down to the raw material that can be reprinted into what we need?

Also: What about this article that popped up here on Y(HN)? http://www.nytimes.com/2012/09/09/magazine/arlene-blums-crus...

Can we print out foam-replacements for open source couches? Does the material have intrinsic "flame retardant" properties? (Probably not but who knows?)

Yeah that one got me planning how to replace all the mattresses and pillows in my house too !

The US Forestry service (certainly by Bill Bryson) is regarded as in thrall with loggers (builds roads for access to heavy equipment, sells trees at a loss acting as a subsidy provider etc.)

You seem surprised by this? The clue is the name: Forestry service - it exists to provide service to the forestry industry.

BUT this isn't necessarily a bad thing! A properly managed forestry industry is a good thing: it provides a cheap, 100% renewable resource, acts as a carbon sink, and acts as a substitute for non-replenishable resources (eg, unmanaged rainforest logging).

At the same time, there is a tension between the renewable aspects of forestry management and the idea of opening new areas for exploitation. That's where the issues are, not around building forestry roads etc.

It's actually called the US Forest Service.

There is needless pedantry on HN and there is needful pedantry on HN

thank you, have a karma point :-) you deserve two for that

There's nothing that suggests this material has to be derived from wood pulp, or from trees. There are plenty of other organisms that produce the type of cellulose they're working with. As mentioned elsewhere, it could be more efficient plants such as bamboo, or even sugarcane grasses, or hemp, for that matter.

NSF says $600 billion industry by 2020? Wow, I'd really like to see the details of how that projection was made.

This would be a good place to start: http://xkcd.com/605/

Just read PG's submarine essay for the first time a couple weeks ago [1], and have been on the lookout for a good example since then.

Bingo.

[1] http://paulgraham.com/submarine.html

How long until people are buying $5000 bikes made of this stuff?

Well, every time I look out at the Molybdenum factory near me, I think, "maybe it's best I get a bike made out of something a little more sustainable."

Bring it on!

Although I guess there's Aluminum. And Titanium. And carbon fiber itself is getting recycling programs (however dubious those are). I'd like to see the impact the entire manufacturing process has on the environment. It doesn't matter what you make it out of, if you have to ship the damn thing half way across the world. Source the wood in Canada, manufacture it in Canada = a win(?)

I get that you're having a dig at the biking crowd, but the major cost of a $5000 bike is the components, not the carbon fiber frame. If the sheer strength is better than Carbon fiber, and still has the same strength to weight ratio, then it probably won't be too long.. especially if the cost is lower.

Sad that hemp is overlooked, it's truly a wonder material. So much so that it sounds fake.

http://www.informationdistillery.com/hemp.htm

http://en.wikipedia.org/wiki/The_Emperor_Wears_No_Clothes

It isn't overlooked, follow the link to the technical report.

http://www.tappi.org/Hide/Events/2012-Nanotechnology-Confere...

It can't still be illegal here in the United States if it wasn't overlooked; ask the average person if non-psychoactive marijuana was used to make cars at one point and most will look at you with confusion, if they even answer.

The history and incredible, incredible use of hemp is extremely overlooked in general. Good luck finding it mentioned more than in passing in a high school text book, or finding a politician aware of the fact that it's almost incomprehensibly better for paper, clothing, and could create - oh my god - so many jobs, the thing a lot of politicians seem to be talking about and promising; but directly preventing (this is both parties, by the way).

Great, another reason to chop trees down.

A wood farming industry could be great for the environment, if done right. As long as you don't burn it, wood is a carbon sink, and as long as you keep replanting trees as you cut them down, you aren't really deforesting.

Basically, assuming this is produced sustainably, for every tonne of this magic wood pulp we produce we suck about 2/3rds of a tonne of CO2 out of the atmosphere. Win-win!

> and as long as you keep replanting trees as you cut them down, you aren't really deforesting.

That may be so, but there are plenty of ways of cutting them down that still leaves the environment devastated. Poorly managed logging utterly ruins the eco-system of the forests.

You're right it can be good for the environment by creating additional economic incentives to manage forests, but only as long as they're managed well, and that's not at all a given.

Is this material dangerous? What if you breathe it in?

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