Re: >H Open Air Space Habitats

Eugene Leitl (
Sun, 2 Mar 1997 19:55:45 +0100 (MET)

On Sat, 1 Mar 1997, Carl Feynman/Forrest Bishop wrote:
> >"Graphite Fiber")=20
> It's a fiber consisting of pure graphite, i.e. carbon. How is this a mis=
> [[As I understand it, Carbon Fiber come in different grades, and is made =
by pyrolyzing=20
> various polymeric hydrocarbons, like rayon or nylon. The resulting fiber =
is (*I think*)
> a mixed up conglomeration of sp2 and sp3 hybrid bonds. Maybe it is mostly=
> I=92ll put that aside aside.]]

It is difficult to denote a boundary between all the carbon allotropes.=20
Diamond is easy, as is graphite: the sheets are planar. The most perfect=20
graphite brand is HOPG (highly ordered pyro graphite, used as SPM=20
standard substrate, and in xray monochromators), whereas the carbon=20
in soot has a semimorphous, turbostratic order of graphite sheets.=20
Buckyballs are easy to spot, but what are buckytubes? I don't think=20
one can call them graphite, since curvature of the concentric sheets is=20
quite large.

Btw carbon fibre production, they first used PAN (polyacrylnitrile)=20
fiber, baked in an oven under tensile load/inert atmosphere. Afair best=20
carbon fibre grade is now spun from coal tar (I know how this sounds...).=
I don't know how the bucky tubes are produced. At a guess, grown from=20
gas phase, using transition metal (nickel?) catalysis?