Carbon Nanotubes

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Charles Talleyrand - 30 Aug 2005 06:07 GMT

Carbon nanotubes might make a *great* spaceship building material.
However nothing is perfect. Are there any known problems with using
carbon nanotubes, beyond cost and manufacturability?

For example, does it disolves in common fuels or water, subject to
hydrogen embrittlement, and/or easily damaged by radiation.

Heck, is the stuff flamable or toxic?

-Thanks
-Charles Talleyrand

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Damon Hill - 01 Sep 2005 10:19 GMT

> Carbon nanotubes might make a *great* spaceship building material.
> However nothing is perfect. Are there any known problems with using
[quoted text clipped - 4 lines]
>
> Heck, is the stuff flamable or toxic?

I don't think any complex structures have been built
yet, as mass production of nanotube fibers has only just
begun to be possible. It would depend on whether the
material has to be laid up like graphite fiber cloth, or
if structures could literally be 'grown'.

Questions have been raised about nanotube dust toxicity,
as with asbestos.

I think it's too early to know reliable answers to your
questions.

I'm very interested in carbon nanotube conductors. Sort of
a room temperature not-quite superconductor, at least lab tests
indicate it's better than even silver. But nowhere near
zero resistance, of course.

--Damon

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Ian Stirling - 01 Sep 2005 10:59 GMT

In sci.space.tech Charles Talleyrand <kitplane01@gmail.com> wrote:

It depends.
The question doesn't really have a stock answer - it's much like asking
"Does glass have any problems..." with regards to fiberglass.
The matrix in which the nanotubes are supported determines most of this.

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Cray74@gmail.com - 01 Sep 2005 13:15 GMT

> Are there any known problems with using
> carbon nanotubes, beyond cost and manufacturability?

Strength. The properties of nanotubes in bulk formats are nowhere near
their individual properties. In fact, it's currently better to use
normal carbon fibers.

> For example, does it disolves in common fuels or water, subject to
> hydrogen embrittlement, and/or easily damaged by radiation.

Carbon nanotube properties are similar to graphite.

> Heck, is the stuff flamable or toxic?

Carbon nanotubes are carbon. Nanotubes will burn just fine, just like
coal, graphite, and diamond.

Mike Miller, Materials Engineer

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John Schilling - 01 Sep 2005 17:41 GMT

>Carbon nanotubes might make a *great* spaceship building material.
>However nothing is perfect. Are there any known problems with using
>carbon nanotubes, beyond cost and manufacturability?

The major problem with carbon nanotubes as a building material is that
carbon nanotubes are not a material, except in the sense that e.g. dust
is a "material".

Carbon nanotubes are a potentially useful *component* of a composite
structural material, but nobody yet knows how to make such a material
or what the other components (e.g. the matrix) would be. The usual
answers don't seem to work for nanotubes, as far as we know. Until
we do know those things, we don't know what the problems will be.

You will, of course, find no shortage of people who will confuse ignorance
with bliss, and so claim that we will Real Soon Now have nanotube/unobtanium
composites with the wondrous strength of carbon nanotubes and absolutely no
problems. Unobtanium, you see, solves all problems and introduces none.

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Earl Colby Pottinger - 03 Sep 2005 20:24 GMT

John Schilling <schillin@spock.usc.edu> :

> In article <1125378461.417523.266060@z14g2000cwz.googlegroups.com>, Charles
> Talleyrand says...
[quoted text clipped - 17 lines]
> composites with the wondrous strength of carbon nanotubes and absolutely no
> problems. Unobtanium, you see, solves all problems and introduces none.

http://www.sciencenews.org/articles/20050820/fob1.asp

http://www.eurekalert.org/pub_releases/2005-08/uota-utd081505.php

http://dsc.discovery.com/news/briefs/20050822/nanotubes.html

I don't see how you can say the above considering the recent reports of the
discovery of how to produce sheets of Nanotubes. This solves atleast two of
the three major problems 1) Production volumes and 2) Directional layout of
the Nanotubes. The idea that resin bonding will remain a long term major
problem seems very unreasonable to me it can be solved by either getting
a resin that bonds better to Nanotubes or get longer nanotubes. It looks
like that will not be a promblem for long (pun intended).

Earl Colby Pottinger

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John Schilling - 06 Sep 2005 00:32 GMT

>John Schilling <schillin@spock.usc.edu> :

>> In article <1125378461.417523.266060@z14g2000cwz.googlegroups.com>, Charles
>> Talleyrand says...

>> >Carbon nanotubes might make a *great* spaceship building material.
>> >However nothing is perfect. Are there any known problems with using
>> >carbon nanotubes, beyond cost and manufacturability?

>> The major problem with carbon nanotubes as a building material is that
>> carbon nanotubes are not a material, except in the sense that e.g. dust
>> is a "material".

>> Carbon nanotubes are a potentially useful *component* of a composite
>> structural material, but nobody yet knows how to make such a material
>> or what the other components (e.g. the matrix) would be. The usual
>> answers don't seem to work for nanotubes, as far as we know. Until
>> we do know those things, we don't know what the problems will be.

>> You will, of course, find no shortage of people who will confuse ignorance
>> with bliss, and so claim that we will Real Soon Now have nanotube/unobtanium
[quoted text clipped - 14 lines]
>a resin that bonds better to Nanotubes or get longer nanotubes. It looks
>like that will not be a promblem for long (pun intended).

I can say the above because faith in the imminent discovery of a suitable
matrix for a nanotube-based composite does *not* tell me what the actual
properties of such a matrix will be, which is what would be needed to
answer the original poster's question. Believing the original poster's
question to be unanswerable with the present state of the art, on account
of one of the necessary components of a future nanotube structural material
being yet unobtained, I told him that his question could not be answered on
account of one of the necessary components of a future nanotube structural
material was unobtanium. I made no claims about the timescale on which
the question would become answerable.

If you have identified a suitable matrix for a nanotube composite, or can
otherwise inform us of the properties of such a material, please do.

Oh, and none of your cited sources actually say anything about production
volumes or layout geometry, beyond "milligrams" and "flat" respectively.
You're assuming those problems have been solved because they would need
to be solved in order for the announced breakthrough to be of practical
importance, but there is no requirement that the press release await such
details.

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Wayne Throop - 06 Sep 2005 21:53 GMT

: John Schilling <schillin@spock.usc.edu>
: Believing the original poster's question to be unanswerable with the
[quoted text clipped - 3 lines]
: account of one of the necessary components of a future nanotube
: structural material was unobtanium.

But "unobtainium" is something that (in some crucial aspect)
*cannot* be obtained, not that it just *hasn't* been obtained yet.
So calling a nanotube matric "unobtainium" is stretching the word
all out of recognition. Scrith is unobtainium. A synthetic two
or ten times as strong as steel, or even "macroscopically as strong
as nanotubes", not so much.

Or put it this way. Unobtanium isn't really proper to use
of things that are simply a Small Matter of Engineering.
It's more Crazy Eddy in nature.

Ah well.

Wayne Throop throopw@sheol.org http://sheol.org/throopw

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Bill Higgins - 07 Sep 2005 22:01 GMT

> But "unobtainium" is something that (in some crucial aspect)
> *cannot* be obtained, not that it just *hasn't* been obtained yet.
[quoted text clipped - 8 lines]
>
> Ah well.

Good point. Besides, nanotubes just stopped being unobtainable.
A company in Cupertino, California has started selling them:
<http://www.pcmag.com/article2/0,1895,1856378,00.asp>

I wouldn't want to try building a space elevator out of them, though.

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Christopher P. Winter - 12 Sep 2005 06:57 GMT

>> But "unobtainium" is something that (in some crucial aspect)
>> *cannot* be obtained, not that it just *hasn't* been obtained yet.
[quoted text clipped - 12 lines]
>A company in Cupertino, California has started selling them:
><http://www.pcmag.com/article2/0,1895,1856378,00.asp>

This is intended as humor, right? You should have put in a smiley ;-).

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Bill Higgins - 15 Sep 2005 01:36 GMT

>> Good point. Besides, nanotubes just stopped being unobtainable.
>> A company in Cupertino, California has started selling them:
>> <http://www.pcmag.com/article2/0,1895,1856378,00.asp>
>
> This is intended as humor, right? You should have put in a smiley ;-).

If you weren't sure, I regret being too subtle. And the Nano Tubes were
somewhat buried in that article.

But let me assure you that Apple now offers Nano Tubes, and will sell you
five for twenty-nine dollars. In assorted colors.

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mcv - 22 Sep 2005 18:01 GMT

In sci.space.tech Charles Talleyrand <kitplane01@gmail.com> wrote:

> Carbon nanotubes might make a *great* spaceship building material.

The most important reason why it's great is ofcourse the possibility
that we may be able to use it to build a space elevator.

> However nothing is perfect. Are there any known problems with using
> carbon nanotubes, beyond cost and manufacturability?
[quoted text clipped - 3 lines]
>
> Heck, is the stuff flamable or toxic?

Flamable yes. Toxic unknown. Conducts electricity very well. In fact I
just read somewhere that a space elevator might actually destroy itself
due to the high currents that would run through the cable.

In order words, interesting stuff that me really need to know a lot more
about before we're going to build something big out of it.

mcv.

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Space Forum / Space Flight / September 2005

Carbon Nanotubes