The three carbon materials described above were prepared by spinning polymer blends consisting of polymers with and without carbon residue after heating. For successful design, in general, there are some requirements as regards the raw polymers. The most important point is that the CPP and TDP have similar softening points and similar viscosities in the spinning process so as to achieve smooth melt-spinning. It is also important that there is no reaction between the polymers, because careful design becomes very difficult when their thermal behaviors are changed by chemical reactions between them. In addition, the CPP should be stabilized as easily as possible from a practical point of view. Two polymer blends of PF/PE and PAN/PMMA were described in the text. They were selected through trial and error on the basis of the requirements described above.
Finally, further possibilities of the polymer blend technique are discussed briefly. Firstly, the polymer blend technique is applicable not only to one-dimensional fibrous carbon material but also to two-dimensional film and plates; carbon film in particular is suitable for this technique.
Secondly, the technique can be used to design fine carbon materials consisting of different carbons, such as a graphitizing and non-graphitizing carbons, by selecting the CPPs skillfully. CNTs consisting of both carbon layers will be developed and open up new application fields.
The polymer blend technique is also applicable for designing other materials such as silicon carbide. Commercially available silicon carbide fibers (Nicalon) are produced by melt-spinning of polycarbosilane. Therefore polycarbosilane can be used in the same manner as CPPs. Silicon carbide nanofiber and nanotubes may be developed. It may be possible that fine materials consisting of carbon and silicon carbide will be designed.
Designing one-dimensional carbon materials (fibrous materials) has been introduced, however the authors are considering possible application to two- and three-dimensional nanomaterials. The presented results deal with carbon-only materials, but the polymer blend technique has great potential in the preparation of various nanomaterials, for example nanomaterials consisting of graphitizing and non-graphitizing carbon as well as nanomaterials consisting of carbon and silicon carbide. We believe this technique to be an important candidate for designing nanocarbon and related materials.