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The significance of the sidewall surface of vertically aligned carbon nanotubes (VACNTs) and the effect of humidity in the determination of VACNT film friction coefficient have been investigated. VACNT films of 2μm thick were sidewall-modified by means of CF 4 and O 2 plasma treatments, and verified for the functionalization of the sidewalls. They were then characterized for wettability...
For safety reasons, the formation of carbon deposits in tokamaks must be limited. To understand how these deposits are formed, a comparative study of the characteristics of carbon deposits collected in TEXTOR and Tore Supra tokamaks has been performed. Both deposits exhibit self-similar morphologies like asparagus tips. Transmission electron microscopy performed on thin foils also reveals structure...
A conductive composite film containing functionalized multi-walled carbon nanotubes (fMWCNTs), gold nanoparticles (Au) with hydroxypropyl-β-cyclodextrin (HPβCD) as catalysts have been synthesized on glassy carbon, gold and on indium tin oxide electrodes by potentiostatic methods. The presence of fMWCNTs and HPβCD in the composite film enhances the active surface coverage concentration of Au by 397...
The bimodal Weibull parameters of polyacrylonitrile-based carbon fibers were obtained from the fiber-bundle tension test. The bimodality increases with increasing high temperature treatment up to 2100°C and then decreases for the highest temperature treatment of 2400°C. The local structure of the fibers was investigated by scanning X-ray microdiffraction using synchrotron radiation. This enables the...
Polyacrylonitrile-based carbon fibers, embedded with multi-wall carbon nanotubes (MWCNTs) in different concentrations, have been prepared by an electrospinning technique. The samples were subjected to oxidative stabilization followed by carbonization and graphitization at temperatures from 1000 to 3000°C. Scanning electron microscopy, X-ray diffraction, and positron annihilation spectroscopy were...
Multi-walled carbon nanotubes (MWCNTs) were chemically functionalized through acid, amine, and heat treatments. These were used in the manufacture of composites using polypropylene (PP) as matrix and two types of compatibilizers, maleic anhydride grafted polypropylene (MA-g-PP) and maleic anhydride grafted styrene–ethylene/butylene–styrene (MA-g-SEBS). PP/MWCNT composites filled with modified MWCNTs...
A low-temperature wet chemistry technique for producing carbon nanoscrolls is described. The technique is based on the use of readily available acceptor-type graphite intercalation compounds. The initial graphite intercalation compound is first exfoliated to produce a suspension of graphene monolayers in ethanol which is subsequently sonicated yielding a suspension of carbon nanoscrolls. The technique...
Activated carbon honeycomb (ACH) monoliths were prepared by extruding of a mixture of bituminous coal and organic additives and subsequent carbonization and steam activation. Preparation parameters that were varied were carbonization temperature and activation time. The carbonization conditions were 500, 650 and 800°C for 1h and the steam activation conditions were 850°C for 2, 4 and 6h. The monoliths...
Zeta potential is a parameter that can be used for studying and predicting colloid stability and surface morphology. Even though zeta potential measurements have been applied to both aqueous and non-aqueous suspensions, theories for colloidal behavior and zeta potential in non-aqueous media are not as well-established as those in aqueous environments. There are few reports on systematic studies of...
WC/carbon composites (WCCs) with high specific surface area were synthesized by the direct carbonization of a mixture of hydroxylpropyl cellulose, polyvinyl alcohol, K 2 WO 4 and K 2 CO 3 at 900°C in flowing N 2 . The resultant material was characterized using X-ray diffraction, thermogravimetric analysis, nitrogen sorption and scanning electron microscopy....
New evidence for the structure of Ni-catalyzed stacked-cup carbon nanofibers (CNFs) has been found. This type of carbon nanofiber exhibits a wide hollow core as well as a large diameter (between 40 and 140nm). The fibers have been produced by the floating catalyst method using natural gas as carbon feedstock, a sulfur compound, and a nickel catalyst. It was found that the catalytic particles are heterogeneous...
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