Carbon Trends最新文献

The analysis method proposed by Ruland et al. is widely used to analyze the void lengths in carbon fibers, but it could not apply to mesophase pitch-based carbon fibers. We thought that the reason for the inability to analyze pitch-based carbon fibers was the length distribution of voids that Ruland neglected. We investigated an analytical method that considers the length distribution of voids in carbon fibers. The proposed new method could be applied to various carbon fibers from polyacrylonitrile and mesophase pitch. The analysis results revealed that the average length of voids in mesophase pitch-based carbon fibers is not only long but also widely distributed. On the other hand, the voids of carbon fibers tend to be longer as the crystallite length is longer in both polyacrylonitrile-based and mesophase-based carbon fibers. It suggests that the growth of void length is strongly influenced by the growth of crystallites in the plane direction.

The self-assembly of graphene oxide (GO) and M13 bacteriophage results in the formation of micro-porous structures, known as GraPhage13 aerogels (GPA). Given the limited applications of aerogels in industry due to their nanomechanical properties, along with the previously observed temperature-dependent characteristics in graphene-based nanocomposites, a thorough exploration of the thermosensitive nanomechanical properties of GPA is essential. Herein, a comprehensive characterisation of the morphology, composition, and spectroscopic analysis of the GPA for a range of temperatures has been conducted and correlated with its nanomechanical properties. Elevated temperatures have been found to lead to gradual removal of oxygen-containing functional groups (OCFGs) from GPA, resulting in increased structural defects and reduced stiffness. Notably, unique nanomechanical behaviours of GPA have been further identified, where the thermal expansion of sp³ bonds exceeds that of a crystalline sp³ structure, while the thermal contraction of sp² bonds in GPA is found to be between graphite and GO. This underscores the impact of GO functionalisation on the thermal expansion behaviour of GPA. The obtained insights enhance the overall comprehension of the temperature annealing impact on GPA and highlight the tunability of its nanomechanical properties, showcasing a broad potential of this novel nanocomposite across a diverse range of applications.

This study used experimental methods to investigate the impact of nitrogen-doped reduced graphene oxide particles (ND-RGOP) reinforcement on thermal and mechanical properties of unidirectional carbon fiber/ epoxy composites (CFRP). In the results, storage modulus and loss modulus significantly increase with the ND-RGOP addition. Besides, glass transition temperature is enhanced with the addition of 0.4 wt% ND-RGOP. In tensile mode, when compared to the baseline (0 weight% ND-RGOP) composites, the elastic modulus in the 0° direction (E₁) enhanced by 8.25 % and 11.39 % with 0.4 (0.4 weight%) and 0.8 (0.8 weight%) ND-RGOP addition, respectively. Besides, the ultimate tensile strength of the 0.4 ND-RGOP/CFRP composites significantly reduced by 16.33 % and 53.08 % in both 0° and 90° directions, respectively, as a result of the fracture mechanism changing from fiber pull out and fiber cracking to fiber breakage which was confirmed by SEM investigations. Furthermore, both the compressive modulus and the shear modulus increased with ND-RGOP reinforcement over 10 %, although the ultimate compressive strength decreases with low ND-RGOP reinforcement. In conclusion, low concentrations of ND-RGOP addition improves the thermal and mechanical properties of CFRP laminates in elastic region, although high concentrations of ND-RGOP decreases the thermal properties.

In the present investigation, carbonized rice husk (CRH) were used as a feedstock for obtaining experimental samples of a carbon monolith. The choice of carbonized rice husk is due to environmental friendliness and availability, optimal physico-chemical and structural features. CRH was obtained by carbonization of rice husks in steam at 900–950 °C, followed by demineralization of 2–15 % nitric acid. The article is devoted to the study of carbon material for use in medicine. In this work, 9 samples of a carbon monolith with different ratios of components were obtained. The samples were obtained on the basis of CRH and plastic mass, which were used as binders. A sample with optimal characteristics was determined: sorption capacity 75.6 %, specific surface according to the multi-current BET method 360.56 m², sorption of ethyl alcohol in biological media 50 %. Sorption capacity was determined using methylene blue dye, which simulates medium molecular weight toxicants. The specific surface area was measured on a sorbtometer using the multiprecision BET method, and the sorption of ethyl alcohol in biological media was determined on a chromatograph. It has been established that the carbon-silicon composition of the sorbent has the mildest sorption compared to the pure carbon composition. Sample No. 8 has a high specific surface area and sorption capacity, which will allow it to absorb a wide range of toxins of various origins, including biological fluids

The synthesis and characterization of graphene oxide (GO) for water related applications has become an increasing area of research. GO was prepared via Hummer's method, and analysed for structure, morphology, thermal stability, and the ability to remove heavy lead ions from solution. In FTIR analyses, hydroxyl, carboxyl and ester groups were found to be on the structure of GO. XRD showed the interlayer spacing to have increased from graphite to graphene oxide, whereby the average crystallite size of GO was 16.13. Then SEM confirmed the morphology of GO to be exfoliated and wrinkled, with stacked layers. In TGA, EG degraded in a single step, while GO degraded in three distinct steps. When using AAS to analyse the Pb (II) ion intake properties of GO, it showed a maximum adsorption of 98.1% for 600 ppm lead ion solution. The Freundlich isotherm model was consistent with this adsorption, meaning that adsorption took place on a heterogenous surface, on a multilayer basis. The value of n for this isotherm was 0.1474, implying a dominant chemical adsorption. A significant contribution was done to the structure of GO, with its metal adsorption properties clearly portrayed.

The volume-localized electronic states (SAMOs) with a maximum of their electron wave functions located in the cavity of nanomaterials have been experimentally and theoretically demonstrated in a fullerene. The existence of SAMOs in single-wall carbon nanotubes (SWCNTs) was also predicted theoretically. In the present paper, these volume states in semiconductor SWCNTs were theoretically investigated using numerical quantum modeling based on density functional theory (DFT). It is shown that the well appears in the center of the tube, whose depth increases with increasing positive charge, since the total potential of a positively charged structure can be represented as the sum of the Coulomb potential and the potential of the atoms of the tube wall. In this context, in addition to the well-studied surface-localized states, states localized in the volume of the cylinder also occur. Using the components of the electric transition dipole moment, the lifetime of the volume states was preliminarily estimated in comparison to the lifetime of the ordinary surface states.

This is a theoretical study of boron-doped single-walled carbon nanotubes. The same topology of primitive nanodomains, located at different positions on single-walled carbon nanotubes, leads to different electronic band structures. We propose a ϕ term. Density functional theory was corrected for van der Waals interactions and used to carry out the periodic boundary condition geometry optimization, where boron formed the topologies of primitive nanodomains. The calculated bulk structure and local structure spectroscopic parameters can be used for comparison with experimental results to confirm the theoretical models.

The recently observed helicity-sensitive response, occurring in graphene based field-effect transistors (FETs) is interpreted as a result of the intrinsic phase asymmetry of these devices and interference of plasmons in the FET channel. The graphene-based plasmonic interferometers presented in this work enable the room temperature detection of THz radiation as well as allows us to distinguish between the rotation direction of circular polarized waves. To illustrate the broadband nurture of the observed effects, similar measurements were carried out at both THz and mid-infrared frequencies. The precise control of the carriers type and their concentration throughout the channel length allows us to demonstrate the helicity-sensitive response over a wide range of the gate potentials (from negative to positive values). We experimentally show that the formation of p–n junction inside the graphene channel leads to additional scattering of excited plasma waves, resulting in the suppression of their interference and consequent reduction of the helicity-sensitive contribution.

In this paper, we report a method for achieving high-yield graphene-containing biocarbon from burlap waste through a simple two-step carbonization process. The first step involves feedstock carbonization at 600 °C, followed by ball milling and then graphitization at 1200 °C using KOH. A comparative analysis between the obtained bio-graphene and commercial graphene revealed superior graphene properties of the burlap-based graphene. Notably, this bio-based graphene exhibited exceptional characteristics such as a very high BET surface area in the range of 1021 m²/g, low defect-to-graphene ratio of 0.12 in the Raman spectra, and an overall yield of 19% wt. These findings highlight the potential of burlap waste as a sustainable precursor for high-quality graphene synthesis and its potential for various applications.

Graphene has been used as a catalyst to reduce the energy barrier for corannulene inversion. For such a catalytic study, corannulene structures are normally assumed to already be in close proximity to graphene, either in the concave-up or concave-down orientation. Here we use both the Lennard-Jones potential (pair-wise dispersion model) and density functional theory calculations to show that corannulene at a distance further away from graphene can adopt various orientations to optimise its interaction with graphene.