Paper Stronger Than Cast Iron

TaeKwonDood writes "All paper is made of cellulose, which at the nanoscale level is quite strong, but paper processing makes large, fragile fibers that break easily. Researchers in Sweden have have come up with a manufacturing process that keeps the fibers small, resulting in 'nanopaper' with over 1.6 times the tensile strength of cast iron (214 megapascals vs. 130 mPa). And since cellulose is the most abundant organic compound on the planet, it's cheap to use compared to other exotic, expensive-to-produce options — such as carbon nanotubes."

1.6 times

[Anonymous Coward]

over 1.6 times the tensile strength of cast iron

Considering that cast iron isn't particularly renown for its tensile strength, being 1.6 times stronger isn't that impressive.

Don't they realize...

[Garridan]

But... cast iron has the tensile strength on the order of concrete. Which is to say, not much at all. Good job guys, you've shown that paper is about as strong as... paper! How did this get published?

Re:Great, but is it fireproof?

[phantomfive]

Could be it doesn't matter for a lot of applications. Houses aren't fireproof, in fact a lot of things arent: clothes, boxes, guitars, plastic, etc. Cast Iron isn't exactly the strongest stuff around, so obviously tensile strength isn't the only important thing in a material. Apparently there is a lot research going on these days about how to make stronger paper. Some links at the bottom of the article.

Re:First!

[icebike]

> No, steel does. That's why I-beams are steel, not
> wood. It's also why the cables in suspension
> bridges are steel, not wood poles.

The same weight of wood would be stronger.

Some respect has to be paid to longevity. Who would use wood suspension cables in termite country?

There are also problems of attaching wood to other objects. Hard to weld wood you know.

Re:Great, but is it fireproof?

[Anonymous Coward]

Houses aren't fireproof

Correction: Wood houses.

There are enough houses, particularly in Europe, which are made mostly of bricks, concrete, and steel. (Floors, even on the second/third levels are made of poured concrete and supported by steel beams.)

They are as close to fireproof as it gets, except perhaps the roof.

Re:A return to former tech?

[The Evil Couch]

Sure, just don't use it in a humid and/or hot environment, where there's a good possibility of sweating on it.

boxes

[Quadraginta]

I would guess the application of interest is shipping boxes and so forth. If you want things well-protected, increasingly important in a shipping industry that uses more robots and conveyor belts and fewer human hands every day, you need strong boxes. Probably even a modest increase in the strength of cardboard would be quite helpful, as it would reduce the fraction of the weight of a shipment that is boxing.

It all depends, really, on whether the processing needed to create "super" paper doesn't cost more than the savings you might enjoy in lower shipping costs per unit weight of product. The fact mentioned in the summary that the original material (wood) is cheap seems quite unimportant.* Steel come essentially from dirt and rock, which is cheap, too. It's the processing that costs.

--------------

* But would I expect a /. editor to know something about materials science and/or economics? I would not.

Re:Great, but is it fireproof?

[fishbowl]

>I understand where you're going with this, but I'd doubt that Martha Stewart would take a paper frying pan seriously.

If it had her company's logo on it, she might.

Re:Great, but is it fireproof?

[marxmarv]

Copper-laminated paper circuit boards are already cheap and available. Now if this stuff is or can be made as flexible as paper, you may have just replaced thin film in flexible circuit applications.

I wouldn't sell it on its toxicity benefits though. The chemicals used to mask and etch pc boards are none too friendly and most paper is absorbent.

I wonder if anyone's tried injection molding short chain cellulose yet... it's better to use carbon we have on the surface already than to mine more and bring it into the surface ecosystem to stay.

Re:First!

[Anonymous Coward]

I'd be interested to know how this stuff stands up to shear: a lot of materials are very strong in one way but incredibly weak in another. Ever try tearing a piece of paper in half by grabbing the two ends and pulling straight apart? It's a lot harder than you would think, but you can easily tear that same piece of paper with two fingers of each hand by applying shear.

Re:1.6 times

[Anonymous Coward]

No it doesn't.

Re:Milli-pascal?

[DrSkwid]

They used that because it's the number they beat.

Re:First!

[EatHam]

Not only that, but steel is also slightly less flammable than wood (or paper).

Re:Great, but is it fireproof?

[PalmKiller]

No, its paper, so don't just throw it away, recycle it.

Re:What is Tensile Strength

[street struttin']

Exactly, for example, ordinary toilet paper has poor tensile strength, resulting in many a brown finger for some. Let's hope this will stop with our new, stronger-than-steel paper. On the downside we may expect a few more red fingers.

Gross.

Tensile Strength?

[Anonymous Coward]

While many people have been great in pointing out the shortcomings in the comparison with cast iron, why anyone would even possibly care about the tensile strength of paper is beyond me as a materials scientist. How many times do you hold a piece of paper at both ends and just try to pull it apart? Tensile strength is probably the worst way to classify paper. The best measure in my mind would be either fracture toughness or shear strength. Since paper is usually used in applications where it is very thin, it is subject to various punctures, tears, and rips. The fracture toughness in the presence of these defects is much more interesting with respect to potential applications. The other possibility would be testing mode III shear strength (aka tearing). Since this is the mode by which probably 90% of all paper products fail, either intentionally or unintentionally, this would seem to be a more true measure of a paper's strength.

Another thing many of you seem to neglect is cost. In case you haven't heard, let me be the first to tell you that to reduce/eliminate defects in materials, even a material as abundant as cellulose, is ridiculously expensive because of the processing costs. So don't think supermarkets are going to be upgrading to this stuff to pack your groceries, and really, I would be surprised if this is anything more than an academic stepping stone.

Re:I always knew Paper was strong!

[stubob]

And now, Paper may beat Scissors as well.