•   Morphology. It was stated that performance improvements are very dependent on the fiber being used, and single wall nanotube SWNT has been measured at 50 GPa (i.e., 10 x better than carbon fiber PAN). There are currently groups attempting to develop materials at the needed sizes that can be put together as composites are today. Regarding the question on weight savings in composites, it was noted that there is the ability to use nanotubes to control morphology but that alignment requires nanometer scale control, which is something that does not exist currently. Potential gains may not be that great; i.e., potentially up to 50 percent with substantial investment. Another area to look at was the composite matrix—where it was suggested that there is a significant opportunity in affecting performance via this area (e.g., gains at the 30 percent level).

•   Thermal system applications. In terms of thermal conductivity, examples were given of nanotubes being used to help carry heat away from electronics/processors. Some groups claim to have seen a 10 percent reduction in the coefficient of thermal expansion (CTE), but that current research has not been focused on this area. It was noted that SWNT have a small but negative CTE, and that designing isotropic materials may be challenging (but also an area in which NASA might benefit).



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