Nanofiber-nanotube composite nanofibers

T. Yang, N. Zhou, Y. Zhang, W. Zhang, K. Jiao, and G. Li, Synergistically improved sensitivity for the detection of specific DNA sequences using polyaniline nanofibers and multi-walled carbon nanotubes composites. Biosens. Bioelectron., 24, 2165—2170 (2009). 

Qi, R. Guo, R. Shen, M. Cao, X. Zhang, L. Xu, J. Electrospun poly (lactic-co-glycolic acid)/halloysite nanotube composite nanofibers for drug encapsulation and sustained release. J. Mater. Chem. 2010, 20 (47), 10622-10629. 

He L X and Tjong S C (2010) Effect of temperature on electrical conduction behavior of polyvinyl-idene fluoride nanocomposites with carbon nanotubes and nanofibers, Curr Nanosci 6 520-524. Bhattacharyya A R, Sreekumar T V, Liu T, Kumar S, Ericson L M, Hauge H and Smalley R E (2003) Crystallization and orientation in polypropylene/single wall carbon nanotube composite. Polymer 44 2373-2377. 

Almecija D, Blond D, Sader J E, Colemanb J N and Boland J J (2009) Mechanical properties of individual electrospun polymer-nanotube composite nanofibers, Carbon 47 2253-2258. 

Wiemann K, Kaminsky W, Gojny FH, Schulte K (2005) Synthesis and properties of syndiotactic poly(propylene)/carbon nanofiber and nanotube composites prepared by in situ polymerization with metallocene/MAO catalysts. Macromol Chem Phys 206 1472-1478... 

Shaffer M, Kinloch IA. Prospects for nanotube and nanofiber composites. Composites Science and Technology. 2004 Nov 64(15) 2281-2. 

Lee H, Mall S, He P, Shi DL, Narasimhadevara S, Yeo-Heung Y, Shanov V, Schulz MJ (2007) Characterization of carbon nanotube/nanofiber-reinforced polymer composites using an instrumented indentation technique. Composites Part B 38 58-65... 

One of the features of the catalysts for production of carbon nanofibers and especially nanotubes consists in a big role of catalyst particle size besides the catalyst chemical composition. The size can not be assigned in advance, and only the change of synthesis method or synthesis condition allows to produce the most active particles. Chemical composition of the catalyst can be changed during pyrolysis. 

A test matrix of about 20 different carbon samples, including commercial carbon fibers and fiber composites, graphite nanofibers, carbon nanowebs and single walled carbon nanotubes was assembled. The sorbents were chosen to represent a large variation in surface areas and micropore volumes. Both non-porous materials, such as graphites, and microporous sorbents, such as activated carbons, were selected. Characterization via N2 adsorption at 77 K was conducted on the majority of the samples for this a Quantachrome Autosorb-1 system was used. The results of the N2 and H2 physisorption measurements are shown in Table 2. In the table CNF is used to designate carbon nanofibers, ACF is used for activated carbon fibers and AC for activated carbon. 

In recent years, we have seen an explosive interest in nanomaterials, in particular in nanofibers, nanofilaments, and nanotubes of the very different chemical composition. The interest arises from the specific mechanical and physicochemical properties of these nano objects, which allow them to be used, for example, as specific adsorbents, catalyst supports, reinforcing components of composite materials, and so on. The most cited generic types of nanomaterials are carbon nanofilaments and nanotubes. Numerous methods for preparing these carbon materials are known. However, the simplest method seems to be thermal pyrolysis of various carbon contain ing precursors (e.g., carbon monoxide, saturated and unsaturated hydro carbons, etc.) in the presence of special catalysts that are typically nanosized particles of nickel, cobalt, iron metals, or their alloys with different metals. 

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