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High-strength composite fibers were prepared from polyvinyl alcohol (PVA) (Degree of polymerization: 1500) reinforced by single-walled carbon nanotubes (SWCNTs) containing few defects. The SWCNTs were dispersed in a 10 wt.% PVA/dimethylsulfoxide solution using a mechanical homogenizer that reduced the size of SWCNT aggregations to smaller bundles. The macroscopically homogeneous dispersion was extruded into cold methanol to form fibers by gel spinning followed by a hot-drawing. The tensile strength of the well-oriented composite fibers with 0.3 wt.% SWCNTs was 2.2 GPa which is extremely high value among PVA composite fibers ever reported using a commercial grade PVA. The strength of neat PVA fibers prepared by the same procedure was 1.7 GPa. Structural analysis showed that the PVA component in the composite fibers possessed almost the same structure as that of neat PVA fibers. Hence a small amount of SWCNTs straightforward enhanced by 0.5 GPa the tensile strength of PVA fibers. The results of mechanical properties and Raman spectra for the SWCNT composites suggest the relatively good interfacial adhesion of the nanotubes and PVA that improves the load transfer from the polymer matrix to the reinforcing phase.

A thermal treatment was applied with CO2 and air for the development of a porous structure. Adsorption isotherms of nitrogen were measured on well-characterized Ni-C nanoparticles. The thermal treatment with CO2 increased the total surface area and micropore volume. In addition the thermal treatment with CO2 increased the hydrogen adsorption., This article is from the Mat. Res. Soc. Symposium Proceedings, v740 p391-396, 2003. This article is from ADA417952 Materials Research Society Symposium Proceedings Volume 740 Held in Boston, Massachusetts on December 2-6, 2002. Nanomaterials for Structural Applications

We have measured magnetotransport of an individual multi-walled carbon nanotube. Though the resistance without magnetic field increases with decreasing temperature (non-metallic) from room temperature down to 2 K, it becomes metallic below 30 K by applying a magnetic field (H ≒ 4 T) perpendicular to the nanotube axis. The transverse magnetoresistance (TMR) below 30 K decreases with increasing magnetic field, and after reaching minimum value around 4 T, it increases. On the other hand, under the intense magnetic field above 6 T the TMR does not show continuous increase but tends to be saturated. The results can be explained by the theoretical prediction of the magnetic-field-induced metal-insulator transition of semiconducting carbon nanotubes., identifier:https://dspace.jaist.ac.jp/dspace/handle/10119/4937

We have measured magnetotransport of an individual multi-walled carbon nanotube. Though the resistance without magnetic field increases with decreasing temperature (non-metallic) from room temperature down to 2 K, it becomes metallic below 30 K by applying a magnetic field (H ≒ 4 T) perpendicular to the nanotube axis. The transverse magnetoresistance (TMR) below 30 K decreases with increasing magnetic field, and after reaching minimum value around 4 T, it increases. On the other hand, under the intense magnetic field above 6 T the TMR does not show continuous increase but tends to be saturated. The results can be explained by the theoretical prediction of the magnetic-field-induced metal-insulator transition of semiconducting carbon nanotubes.