Carbon Nanotubes in Nanofibers

TABLE 6.1 Tensile properties and electrical resistivity of melt-spun conventional composite fibers of polypropylene/carbon fiber (spun at 220°C and a draw ratio of 1.0) 

Carbon Fiber Volume Fraction (%) Tensile Strength (MPa) Young s Modulus (GPa) DC Resistivity (fl m) 

Carbon nanotubes generally tend to exist as bundles or even networks of aggregates because of strong nonbonded interactions. To exploit their full potential as fillers, however, techniques that achieve near-complete dispersion of nanofibers and improve tbeir compatibility with the polymers, need to be developed. Data on single-fiber measurements that illustrate the reinforcing effect of CNTs in fibers are sparse in the literature (Pomes et al. 2006 Moore et al. 2004). Recent studies on melt-spun conventional composite fibers of polypropylene illustrates reinforcement by CNTs (Moore et al. 2004). 

---

Serp, P, Corrias, M., and Kalck, P. 2003. Carbon nanotubes and nanofibers in catalysis. Applied Catalysis A General 253 337-358. 

A wide range of nanosfructured carbons has been discovered since fhe original discovery of carbon nanotubes (CNTs) by lijima in 1991. Carbon nanotubes and nanofibers are nanoscale cylinders of rolled up graphene sheets. 

Lee, K., Zhang, J., Wang, H., and Wilkinson, D. P. Progress in the synthesis of carbon nanotube- and nanofiber-supported Pt electrocatalysts for PEM fuel cell catalysis. Journal of Applied Electrochemistry 2006 36 507-522. 

In view of practical application, the carbon nanotubes or nanofibers were saturated with molecular hydrogen under relatively mild conditions the hydrogen pressure did not exceed 10 -r 12 MPa at room or liquid nitrogen temperatures. The data of the application research were reviewed, e.g., by Dillon and Heben (2001). 

Fig. 11.5 IR diffuse reflection spectra of graphite nanofibers and single-walled carbon nanotubes in the initial state, after saturation with hydrogen at 9 GPa, after removal of about 40% of absorbed hydrogen, and after degassing annealing. T = 300 K...

For large scale production of carbon nanotubes and nanofibers chemical vapor deposition (CVD) method is most effective. Acetylene, ethylene, propylene, methane, natural gas (consisting predominantly of propane), carbon monoxide were used as a source of carbon [ 1 -8] (in view of large number of publications on CNT synthesis these references are selected arbitrary). Ethylene and possibly propylene are most convenient carbon sources for mass synthesis of high quality multiwall CNT (MWNT). 

Besides the traditional markets for carbon, some novel applications for the carbon produced via methane decomposition are discussed in the literature. Kvaemer has initiated R D program to investigate the potential of novel grades of carbon black as a storage medium for hydrogen, and as a feedstock for the production of solar grade silicone.35 The production of carbon nanotubes and nanofibers via solar thermal decomposition of methane over supported Co and Ni catalysts, respectively, was also reported.36... 

Carbon nanotubes and nanofibers have lately attracted great attention in nanomedicine including their potential use as drug carriers, although there are also considerable concerns associated with their safety (Lange et al., 2003 Muller et al.,... 

At the beginning of the 2U century, it is thought that the improvement of the existing chemical industry will pass through the development of new kinds of catalysts to meet the latest environmental requirements. Since their discovery in 1991 [1], carbon nanotubes and nanofibers have received increasing interest in academic research and for several potential applications [2-4]. It has been reported by different authors that carbon nanofibers could be efficiently used as catalyst support for several catalytic reactions either in gas or in liquid phase [5-7], In both cases, the carbon nanofiber based catalysts always exhibited higher catalytic performances compared to those observed on equivalent conventional catalysts. 

---