Micro-coiled carbon fibers were prepared by catalytic pyrolysisof acetylene with nano-sized nickel powder catalyst using the substrate method. The morphology of micro-coiled carbon fibers was observed through field emission scanning electron microscopy. It was found that the fiber and coil diameter of the obtained micro-coiled carbon fibers is about 500—600 nm and 4—5 μm, respectively. Most of the micro-coiled carbon fibers obtained were regular double carbon coils, but a few irregular ones were also observed. On the basis of the experimental observation, a solid catalytic growth mechanism of micro-coiled carbon fibers was proposed.
Grand canonical Monte Carlo molecular simulations were carried out for hydrogen adsorption in single-walled carbon nanotubes. It was found that variations in chemical potential may result in a great change in the hydrogen storage capacity of single-walled carbon nanotubes. Hydrogen adsorption isotherms of single-walled carbon nanotubes at 298.15 K were calculated using a modified chemical potential, and the result obtained is closer to the experimental results. By comparing the experimental and simulation results, it is proposed that chemical adsorption may exist for hydrogen adsorption in single-walled carbon nanotubes.
Nanosized inner cavities of carbon nanotubes (CNTs) afford quasi-one-dimensional (1D) confined space, in which materials adsorbed or filled are of reactivity greatly different from the materials adsorbed on a planar surface and quite a number of curious physicochemical processes will possibly occur. In other words, 1D CNT nanochannels may serve as 搉anosized test tubes? In this article, on the basis of the unique chemical and physical properties of CNTs, the latest progresses of the research on peculiar inner-tubular physicochemical processes of CNTs are briefly reviewed from several aspects. The extraordinary 1D adsorption, capillary filling and nanoscale-confined reaction are discussed in detail. Moreover, the characteristics of 搉anosized test tubes?are summarized and many unfamiliar inner cavity chemical processes are expected. Finally, the future direction and challenges on basic researches and potential applications of inner-tubular chemistry of CNTs are discussed.
Carbon nanofiber (CNF)-reinforced polypropylene (CNF/PP) composites with different CNF contents were preparedby melt mixing, and the mechanical properties and crystallization behavior of the CNF/PP composites obtained wereinvestigated. It was found that the tensile modulus of the composites was increased with the addition of CNFs, buttheir elongation at break and fracture strain energy were decreased, while the tensile strength of the composites wasfirstly increased and then decreased due to the agglomeration of CNFs at higher loading. Nonisothermal crystallizationanalysis showed that the CNFs played a role as nucleating agent in PP matrix, which led to increment in thecrystallization rate and the degree of crystallinity of PP. Moreover, X-ray diffraction studies showed that the CNFsincorporated in the PP matrix favored the growth of (040)-oriented PP crystals. With the increase in the CNFcontent, the nucleating and orientation roles of the CNFs were obviously enhanced.
