Grown Fibers

Detailed accounts of fibers and carbon-carbon composites can be found in several recently published books [1-5]. Here, details of novel carbon fibers and their composites are reported. The manufacture and applications of adsorbent carbon fibers are discussed in Chapter 3. Active carbon fibers are an attractive adsorbent because their small diameters (typically 6-20 pm) offer a kinetic advantage over granular activated carbons whose dimensions are typically 1-5 mm. Moreover, active carbon fibers contain a large volume of mesopores and micropores. Current and emerging applications of active carbon fibers are discussed. The manufacture, structure and properties of high performance fibers are reviewed in Chapter 4, whereas the manufacture and properties of vapor grown fibers and their composites are reported in Chapter 5. Low density (porous) carbon fiber composites have novel properties that make them uniquely suited for certain applications. The properties and applications of novel low density composites developed at Oak Ridge National Laboratory are reported in Chapter 6. 

Methane, or rather natural gas (which may contain carbon oxides, higher hydrocarbons, and inert gases), is of great interest as a source of pyrolytically grown fibers because of its relatively low cost. 

Figure 8. Number of fibers counted in the camera s focal plane 2.5 cm below the furnace centerline after a number of standard growth experiments where the hydrogen jacket pressure was held constant at the values shown. Bottom curve refers to a series of 304 tubes. In the top curve 304 tubes which had previously grown fibers and whose surfaces were treated with Fe(NO ) were used.

Tibbets, G.G., Meisner, G.P. and Oik, Ch.H. (2001) Hydrogen storage capacity of carbon nanotubes, filamenta, and vapor-grown fibers, Carbon 39, 2291-... 

The macroscopic structure of this fiber is shown in Figure 3 revealing a smooth parallel structure of elemaitary microfibrils, which can be easily peeled off in the fiber growth direction. The grown fibers show flat ribbon-like structures having a width ranging firom 20 mm to 300 rma... 

Figure 3. (a) Typical view of surface grown fiber at optimum conditicm (150 x). (b) Tyjacal view of surface grown fiber at optimum condition (1000 x). 

Figure 4. E ect of rotor qieed on the Urefiingenoe of surfece grown fibers.

Figure 6. Effect of rotor speed on the tweaking stress of surface grown fibers.

Figure 7. Effect of take-up speed on the heat of fusion of surface grown fibers.

Figure 10. Effect d. take-up speed on the breakiiig stress d surfece grown fibers.

Figure 12. E ect of conoenlratioa on fair ingence of surface grown fibere.

Figure 13. fect of conoentration on tiie breaking strain of surface grown fibers. 

Figure 14. Effect of cancentraticHi on the tensile modulus of surface grown fibers.

Figure 17. Effect of crystallization temperature on the birefringence of surface grown fibers.

It is well worth reemphasizing that short vapor-grown whiskers and fibers, (Chapter 2), and continuous vapor-grown fibers (Chapter 3) have higher mechanical properties than the same... 

Figure 8.25 Young s modulus of as-grown fibers as a function of the fiber diameter, which have seen a maximum of 1130°C. All of the fibers were grown simultaneously. Source Reprinted from Tibbetts GG, Beetz CP Jr Mechanical properties of vapor grown carbon fibers, J Phys D AppI Phys, 20, 292, 1987.

Tibbetts, G., Meisner G,. Oik C, (2001). Hydrogen Storage Capacity of Carbon Nanotubes, Filaments, andVapor-grown Fibers. Carbon. 39, 2291-2301. 

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