Fiber nanofiber

Porous carbons constitnte a fascinating kind of material. Different types with distinctive physical forms and properties (i.e., activated carbons, high-surface-area graphites, carbon blacks, activated carbon cloths and fibers, nanofibers, nanotubes, etc.) find a wide range of indnstrial applications in adsorption and catalysis processes. The main properties of these materials that make them very useful as catalyst supports, as well as some of their applications, have been described. The use of carbon as a catalyst support relies primarily on the relative inertness of its surface, which facilitates the interaction between active phases or between active phases and promoters, thus enhancing the catalytic behavior. This makes porous carbons an excellent choice as catalyst support in a great number of reactions. 

Applications - appliance, automotive, bottles, electrical, fibers, nanofibers, powder coatings, support for enzyme immobilization ... 

Bortz, D., Merino, C., Martin-Gullon, I., 2011. Mechanical characterization of hierarchical carbon fiber/nanofiber composite laminates. Composites Part A 42, 1584—1591. 

Fiber reinforcement is controlled primarily by the mechanical properties of the fibers, their axial ratio, and the mechanical coupHng between the fibers and the matrix (e.g., see [126]). Electrospim nanofibers tend to display enhanced mechanical properties due to the self-organization controlUng fiber formation during electrospiiming. Furthermore, the axial ratio of the fibers, nanofibers with diameters of about 10 or 100 nm, can be 100 to 1000 times... 

Structure The polymers are produced as powders or as films on the electrodes. Most conductive polymers have a fibrous structure, each fiber consisting of hundreds of strands of polymer molecules. Techniques exist to control fiber preparation so as to obtain nanofibers expected to be particularly useful as catalyst substrates and in electronic applications (MacDiannid, 2000). 

Normal transmission IRLD can also be used to characterize polymeric fibers, although scattering can induce sloping baselines. Raman spectroscopy then becomes a convenient alternative. Rutledge et al. have recently probed the orientation in electrospun nanofibers composed of a core of Bombyx mori fibroin and an outer shell of poly (ethylene oxide) [24], The orientation values were low, less than 0.1, as is often the case in electrospun fibers. 

A wide variety of carbon materials has been used in this study, including multi-wall carbon nanotubes (sample MWNT) chemically activated multi-wall carbon nanotubes (sample A-MWNT)16, commercially available vapor grown carbon nanofibers (sample NF) sample NF after chemical activation with K.OH (sample A-NF) commercially pitch-based carbon fiber from Kureha Company (sample CF) commercially available activated carbons AX-21 from Anderson Carbon Co., Maxsorb from Kansai Coke and Chemicals and commercial activated carbon fibers from Osaka Gas Co. (A20) a series of activated carbons prepared from a Spanish anthracite (samples named K.UA) and Subituminous coal (Samples H) by chemical activation with KOH as described by D. Lozano-Castello et al.17 18 activated carbon monoliths (ACM) prepared from different starting powder activated carbons by using a proprietry polymeric binder from Waterlink Sutcliffe Carbons, following the experimental process described in the previous paper13. 

The formation of carbon over Ni, Fe, and Co has been extensively studied, both for catalytic applications " and for dusting or dry corrosion, the problem of pitting when steels are exposed to hydrocarbons at high temperatures. Recently, the properties of Ni for forming carbon have even been proposed for use in the manufacture of carbon nanofibers. The mechanism on each of these metals, shown diagrammatically in Figure 8a, involves deposition of a carbon source onto the metal surface, dissolution of the carbon into the bulk of the metal, and finally precipitation of carbon as a fiber... 

Within a composite material, much of the ultimate strength comes from the intimate contact the fiber has with the matrix material. Nanofibers allow more contact between the fiber (on a weight basis) and the matrix resulting is a stronger composite because of an increased fiber surface matrix interface. 

Nanocomposites employ nanofibers that allow for much greater fiber-resin surface contact per mass of fiber and consequently they generally offer greater strength in comparison to similar non-nanocomposites. 

In this chapter, we reviewed the structure-controlled syntheses of CNFs in an attempt to offer better catalyst supports for fuel cell applications. Also, selected carbon nanofibers are used as supports for anode metal catalysts in DMFCs. The catalytic activity and the efficiency of transferring protons to ion-exchange membranes have been examined in half cells and single cells. The effects of the fiber diameter, graphene alignment and porosity on the activity of the CNF-supported catalysts have been examined in detail. 

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