Re: Zylon Superfiber
I should mention that nanotubes may not be necessary since polymer fibers have nearly achieved the strength required to construct, say, a skyhook or space elevator. Toyobo Corporation in Japan currently sells Zylon Superfiber whose constituent fibers have a tensile strength of approximately 5.8 billion Pascals. I contacted them and found out that the strength of the macroscopic yarns is only 2/3rds lower, at approximately 1.74 billion Pascals.
Polymer-based fibers are carbon-based, as are nanotubes. And whether it is necessary to derive superstrong fibers from nanotubes or not remains to be seen.