Micro-sized Carbon Fiber Research Articles

Orientation of carbon fiber in magnesium-doped hydroxyapatite and its effect on mechanical and tribological properties of carbon fiber reinforced composites

Carbon fiber (CF) reinforced magnesium-doped hydroxyapatite (Mg-HA) composites have been shown possess excellent mechanical performance and tailored biological properties. In order to further explore the effect of the orientation for short CF reinforced Mg-HA composites for mechanical and tribological properties. Micro-sized CF was oriented in Mg-HA by a self-developed mold and highly oriented CF reinforced magnesium doped hydroxyapatite (OCF/Mg-HA) composites were prepared by spark plasma sintering (SPS). The morphology, structure, wettability, mechanical properties and tribological properties of the composites were investigated. The results show that the average contact angle of oriented CF/Mg-HA composites was 67.65° and had good hydrophilicity. Compressive strength of OCF/Mg-HA in the direction parallel to the fiber was 129.8 MPa, which met the requirements of mechanical properties of human cortical bone. In addition, the wear resistance of OCF/Mg-HA ceramics was significantly improved by the addition of CF. The average friction coefficient of OCF/Mg-HA ceramics in the direction parallel to the fiber was 0.157. OCF/Mg-HA ceramics exhibited excellent tribological properties and mechanical properties which were close to that of human load-bearing bone due to the oriented arrangement of CF. This laid a foundation for the clinical application of OCF/Mg-HA ceramics in the repair of bone defects at load-bearing sites.

Rationally engineering a hierarchical porous carbon and reduced graphene oxide supported magnetite composite with boosted lithium-ion storage performances

Ferric gallate (Fe-GA), an ancient metal–organic framework (MOF) material, has been recently employed as an eco-friendly and cost-effective precursor sample to synthesize a porous carbon confined nano-iron composite (Fe/RPC), and the Fe element in the Fe/RPC sample could be further oxidized to Fe3O4 nanocrystals in a 180 °C hydrothermal condition. On this foundation, this work reports an optimized approach to engineering a hierarchical one-dimensional porous carbon and two-dimensional reduced graphene oxide (RGO) supporting framework with Fe3O4 nanoparticles well dispersed. Under mild hydrothermal condition, the redox reaction between metal iron atoms from Fe/RPC and surface functional radicals from few-layered graphene oxide sheets (GO) is triggered. As a result, reinforced microstructure and improved atomic efficiency have been achieved for the Fe3O4@RPC/RGO sample. The homogeneously dispersed Fe3O4 nanoparticles with controlled size are anchored on the surface of the larger sized RGO coating layers while the smaller sized RPC domains are embedded between the RGO sheets as spacer. Challenges including spontaneous aggregation of RPC, over exposure of Fe3O4 nanoparticles and excessive restacking of RGO have been significantly inhibited. Furthermore, micro-sized carbon fiber (CF) is chosen as a structural reinforcement additive during electrode fabrication, and the Fe3O4@RPC/RGO sample delivers a good specific capacity of 1170.5 mAh·g−1 under a current rate of 1000 mA·g−1 for 500 cycles in the half cell form. The reasons for superior electrochemical behaviors have been revealed and the lithium-ion storage performances of the Fe3O4@RPC/RGO sample in the full cell form have been preliminarily investigated.

Micro-sized carbon fiber: a new supporting material for microorganisms in the decomposition of nitrogen and phosphorus nutrients in wastewater with high salinity

Eutrophication, which kills fish, mussels and other animals in aquatic ecosystem, is the response tothe excess of nitrogen and phosphorus nutrients. In this study, activated carbon fiber prepared frompoly(acrilonitrile) PAN, a carbonaceous material of micro size with high specific area, has been evaluated tobe able to create microbiological membranes that could be used in the decomposition of nitrogen and phosphoruscompounds in wastewater with salinity up to 30 ppt. Utilization of carbon fiber in the sustainabletreatment of highly contaminated aquaculture wastewater with organic and inorganic pollutants was consideredas a promising application in Khanh Hoa province, Vietnam, with great treatment capacity, low system’sprice and implementation’s cost.

A mussel-inspired hybrid copolymer adhered to chitosan-coated micro-sized carbon fiber aerogels for highly efficient nanoparticle scavenging

A hybrid PDA/PEI copolymer grafted onto chitosan-coated micrometer-sized carbon fiber aerogels was successfully fabricated by a layer-by-layer assembled strategy and was then used for enhanced removal of Ag and Au nanoparticles from water.

Development of Ultra-Fast Nanostructured Glucose Biosensor - Stoichiometry and Activity

Neuronal activities are very fast and occur in the time scale of milliseconds. The current sensors for monitoring non-electroactive molecules in neuronal activities respond in the time scale of subsecond or several seconds. In order to capture the rapid transients of metabolites and non-electroactive molecules involved in neuronal activities in the brain, our lab recently showed a new enzyme based electrochemical sensor that can detect neurotransmitter acetylcholine in milliseconds. Subsequently, the glucose sensor is currently under development.Glucose is well known as the ubiquitous energy source. Extensive evidence indicates that glucose has significant effects on learning, memory processes and cognitive functions in humans. In our lab, micro-sized carbon fiber electrodes are firstly modified by gold nanoparticles (AuNP) to increase the surface area and surface curvature, and then glucose oxidase (GOx) is attached on the AuNP surface as the second layer which can induce the reaction of glucose with oxygen, subsequently the electronic signal produced from reaction will be captured by the electrochemical instrument. In order to optimize the sensor's working efficiency, the amount of GOx fully covering AuNP surface in bulk solution was quantified by flocculation assay using UV-Vis spectrophotometer and by direct and indirect quantification of stoichiometry using fluorescent spectrophotometer. The difference of enzyme activity between free GOx and immobilized GOx on AuNP was also studied. Later soon, the sensitivity, selectivity and stability of glucose sensor will be further investigated.

Effects of nano-sized and micro-sized carbon fibers on the interlaminar shear strength and tribological properties of high strength glass fabric/phenolic laminate in water environment

In order to clarify the effects of carbon fiber size on the properties of carbon fiber/high strength glass fabric (HSGF)/phenolic laminate, two kinds of laminates modified by nano-sized carbon fibers (CNFs) and micro-sized carbon fibers (CMFs), were respectively fabricated. The interlaminar shear strength (ILSS) and tribological properties of HSGF/phenolic laminates modified by CNFs and CMFs in water environment were comparatively investigated. Results showed that CNFs at proper contents ranging from 1.0% to 3.0% can enhance ILSS of HSGF/phenolic laminate, while CMFs deteriorated the ILSS. After water immersion, ILSS of the laminates modified by CNFs at 1.0–3.0% were just slightly decreased; however, those of the laminates modified by CMFs suffered larger drop. On the other hand, however, CMFs were more effective than CNFs in improving the wear resistance of HSGF/phenolic laminate in water.

Laboratory Investigation of Biochar-Modified Asphalt Mixture

The United States is promoting the establishment of a bio-based economy, generating energy and fuels from renewable organic matters rather than fossil fuels. Byproducts such as fractions of biochar not suitable for biofuel production are drawing extensive attention. (“Biochar” is defined by Oxford's online dictionary as “charcoal produced from plant matter and stored in the soil as a means of removing carbon dioxide from the atmosphere.”) Recently, biochar produced with different production parameters was tried as an asphalt modifier owing to its carbon origin and proved to be positive in binder modification. This study evaluated the performance of hot-mix asphalt modified by one type of pyrolytic biochar with controlled production parameters. Typical carbon black powder pellets and microsized carbon fiber were selected as the reference additives. Multiple laboratory binder and performance tests were conducted to evaluate the rheological properties of the modified binder, rutting resistance, moisture susceptibility, and cracking resistance of asphalt mixtures. On the basis of test results, the biochar evaluated in this study proved to be an effective modifier in reducing the temperature susceptibility of the binder and thus increased the rutting, moisture, and cracking resistance of hot-mix asphalt. In addition, biochar proved to be a better asphalt modifier than did carbon black and carbon fiber.

Fabrication and superhydrophobicity of fluorinated carbon fabrics with micro/nanoscaled two-tier roughness

Superhydrophobic carbon fabric with micro/nanoscaled two-tier roughness was fabricated by decorating carbon nanotubes (CNTs) onto microsized carbon fibers, using a catalytic chemical vapor deposition and subsequent fluorination surface treatment. The superhydrophobic surfaces are based on the regularly ordered carbon fibers (8–10 μm in diameter) that are decorated by CNTs with an average size of 20–40 nm. The contact angle of water significantly increases from 148.2 ± 2.1° to 169.7 ± 2.2° through the introduction of CNTs. This confirms that the wettability of carbon fabric changes from hydrophobicity to superhydrophobicity due to structural transformation. This finding sheds light on how the two-tier roughness surface induces superhydrophobicity of rough surfaces, and how the presence of CNTs reduces the area fraction of a water droplet in contact with the carbon surface with two-tier roughness.

Multicomponent and Multidimensional Carbon Nanotube Micropatterns by Dry Contact Transfer

One of the critical aspects of nanotechnology is to assemble different nanoscale components into a single system. In such a multicomponent system, the overall functionality depends strongly on the precise location and structural characteristics of each of the constituent components. In this context, we have prepared multicomponent micropatterns of silica particles interposed within the discrete areas of aligned multiwall carbon nanotubes. The patterns were fabricated by dry contact transferring aligned carbon nanotubes onto a tape pre-patterned with a thin layer of gold structure, followed by region-specific adsorption of thiol-modified silica particles onto the gold surface from solution. The dry contact transfer technique has further enabled us to develop micropatterns of aligned single-wall carbon nanotubes with interdispersed non-aligned multiwall carbon nanotubes and microsized carbon fibers sheathed with micropatterned aligned carbon nanotubes.

Carbon Microfibers Sheathed with Aligned Carbon Nanotubes: Towards Multidimensional, Multicomponent, and Multifunctional Nanomaterials

Multicomponent and multifunctional hybrid structures based on microsized carbon fibers sheathed with aligned carbon nanotubes and their derivatives have been successfully prepared, and have been demonstrated to be an effective means for connecting nanoscale entities to the outside world and to possess interesting electrochemical properties attractive for a wide range of potential applications, including in methanol direct fuel cells and highly sensitive biological and chemical sensors. Judicious modification of the carbon-fiber-supported aligned carbon nanotubes with various functional moieties could lead to a class of novel multidimensional, multicomponent, and multifunctional materials of practical significance.

FIB-SIMS investigation of carbazole-based polymer and copolymers electrocoated onto carbon fibers, and an AFM morphological study

The work presented in this paper reports preliminary results obtained by focused ion beam-secondary ion mass spectroscopy (FIB-SIMS) analysis in the study of micro-sized carbon fiber electrocoated by conjugated-nonconjugated polymers such as poly( N-vinylcarbazole-co-methylthiophene), poly( N-vinylcarbazole-co-vinylbenzene sulfonic acid) and polycarbazole. The aim of this study was to investigate by FIB-SIMS analysis the presence and concentration gradient of certain elements via depth profiling of the coating on selected carbon fibers. The presence of dopant ions together with their gradient of concentration in the coating layer was elucidated as well as the thickness of the copolymer layer electrocoated onto the carbon surface. AFM analysis performed on the electrocoated fibers yielded information regarding the surface morphology and roughness.