Lignin-Based Carbon Fibers: Formation, Modification and Potential Applications

AbstractWe successfully synthesized helical core-shell crystalline SiC/SiO2 nanowires, core-shell crystalline SiC/C nano-crosses and well-aligned core-shell crystalline SiC/C fibers by using a chemical vapor deposition technique. For the helical crystalline SiC/SiO2 nanowires, the SiC core typically has diameters of 10-40 nm with a helical periodicity of 40-80 nm and is covered by a uniform layer of 30-60 nm thick amorphous SiO2. Detailed structural characterizations suggested that the growth of this novel structure was induced by screw dislocations on the nanometer scale. For the core-shell nanocrosses, the crystalline SiC core typically has diameters of 10 to 40 nm and is covered by a uniform layer of 80-110 nm graphitic carbon. The wellaligned SiC/C fibers were shown to be formed by two sequential steps: catalytic SiC growth and graphitic carbon nano-sheets coating. The helical nanowires and core-shell nanocrosses may have potential applications in nano-electronics. The formation mechanism of the carbon fibers suggested that fabrication of field emission filament carbon nano-fibers may be realized by using the aligned crystalline nanowires as templates.

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New Progress on Fiber-Based Thermoelectric Materials: Performance, Device Structures and Applications

Materials ◽

10.3390/ma14216306 ◽

2021 ◽

Vol 14 (21) ◽

pp. 6306

Author(s):

Yanan Shen ◽

Chunyang Wang ◽

Xiao Yang ◽

Jian Li ◽

Rui Lu ◽

...

Keyword(s):

Power Systems ◽

Carbon Fibers ◽

Thermoelectric Materials ◽

Rapid Development ◽

Wearable Electronics ◽

Hybrid Fibers ◽

Surrounding Environment ◽

Device Structures ◽

Potential Applications ◽

Self Powered

With the rapid development of wearable electronics, looking for flexible and wearable generators as their self-power systems has proved an extensive task. Fiber-based thermoelectric generators (FTEGs) are promising candidates for these self-powered systems that collect energy from the surrounding environment or human body to sustain wearable electronics. In this work, we overview performances and device structures of state-of-the-art fiber-based thermoelectric materials, including inorganic fibers (e.g., carbon fibers, oxide fibers, and semiconductor fibers), organic fibers, and hybrid fibers. Moreover, potential applications for related thermoelectric devices are discussed, and future developments in fiber-based thermoelectric materials are also briefly expected.

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Processing Iron Oxide Nanoparticle-Loaded Composite Carbon Fiber and the Photosensitivity Characterization

Fibers ◽

10.3390/fib7030025 ◽

2019 ◽

Vol 7 (3) ◽

pp. 25 ◽

Cited By ~ 2

Author(s):

Yong Gan ◽

Christina Yu ◽

Niousha Panahi ◽

Jeremy Gan ◽

Wanli Cheng

Keyword(s):

Iron Oxide ◽

Carbon Fibers ◽

Elevated Temperatures ◽

Open Circuit ◽

Metallographic Analysis ◽

Iron Oxide Nanoparticle ◽

Light Illumination ◽

Chain Polymer ◽

Potential Applications ◽

Oxide Nanoparticle

In this work, iron oxide nanoparticle loaded carbon fibers were prepared by electrohydrodynamic co-casting a polymer and particle mixture followed by carbonization. The precursor used to generate carbon fibers was a linear molecular chain polymer: polyacrylonitrile (PAN). A solution containing iron (II, III) oxide (Fe3O4) particles and the PAN polymer dissolved in dimethylformamide (DMF) was electrohydrodynamically co-cast into fibers. The fibers were stabilized in air and carbonized in hydrogen at elevated temperatures. The microstructure and composition of the fibers were analyzed using scanning electron microscopy (SEM). A quantitative metallographic analysis method was used to determine the fiber size. It was found that the iron (II, III) oxide particles distributed uniformly within the carbonized fibers. Photosensitivity of the particle containing fibers was characterized through measuring the open circuit potential of the fiber samples under the visible light illumination. Potential applications of the fibers for photovoltaics and photonic sensing were discussed.

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Increasing the value of a biorefinery based on hot-water extraction: Lignin products

TAPPI Journal ◽

10.32964/10.32964/tj11.1.19 ◽

2012 ◽

Vol 11 (1) ◽

pp. 19-26 ◽

Cited By ~ 22

Author(s):

BILJANA M. BUJANOVIC ◽

MANGESH J. GOUNDALKAR ◽

THOMAS E. AMIDON

Keyword(s):

Carbon Fibers ◽

Aromatic Compounds ◽

Low Cost ◽

Hot Water ◽

Water Extraction ◽

Hot Water Extraction ◽

Isolation And Characterization ◽

Potential Applications

In conventional pulping technologies, lignin is used mainly as a low-cost source of energy. Small quantities of industrially produced lignin are used for the production of chemicals and materials. Biorefinery technologies are emerging that have an ultimate goal of replacing fossil sources for the production of fuels and other products. To achieve this goal effectively, biorefinery technologies must take advantage of lignin as the most abundant natural aromatic polymer and use it to add higher-value products to product portfolios. Lignin has the potential to be used in making a broad range of high-quality products, including carbon fibers, thermoplastics, and oxygenated aromatic compounds. Existing processes focus primarily on the quality of cellulose and result in a severely modified and contaminated lignin of relatively low value. Lignin produced in more flexible biorefinery operations is more uniform and less contaminated than currently available industrial lignins, opening the door for broader applications of lignin and lignin products. The results of isolation and characterization of lignin dissolved during hot-water extraction and some potential applications of this lignin are discussed.

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Carbon fiber skeleton/silver nanowires composites with tunable negative permittivity behavior

EPJ Applied Metamaterials ◽

10.1051/epjam/2020019 ◽

2021 ◽

Vol 8 ◽

pp. 1

Author(s):

Yan An ◽

Jinyuan Qin ◽

Kai Sun ◽

Jiahong Tian ◽

Zhongyang Wang ◽

...

Keyword(s):

Dielectric Constant ◽

Composite Material ◽

Carbon Fibers ◽

Silver Nanowires ◽

Negative Permittivity ◽

Conductive Network ◽

Impregnation Process ◽

Absolute Value ◽

Potential Applications ◽

Different Content

With the development of periodic metamaterials, more attention has been paid to negative permittivity behavior due to great potential applications. In this paper, silver nanowires (AgNWs) were introduced to the porous carbon fibers (CFS) by an impregnation process to prepare CFS/AgNWs composites with different content of AgNWs and the dielectric property was investigated. With the formation of conductive network, the Drude-like negative permittivity was observed in CFS/AgNWs composites. With the increase of AgNWs, the connectivity of conductive network became enhanced, the conductivity gradually increases, and the absolute value of the negative dielectric constant also increases to 8.9 × 104, which was ascribed to the enhancement of electron density of the composite material. Further investigation revealed that the inductive characteristic was responsible for the negative permittivity.

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FTIR Study of the retardation effect of boric acid on the cyclization reaction of polyacrylonitrile

e-Polymers ◽

10.1515/epoly.2009.9.1.169 ◽

2009 ◽

Vol 9 (1) ◽

Cited By ~ 3

Author(s):

Qin Ouyang ◽

Lu Cheng ◽

Haojing Wang ◽

Kaixi Li

Keyword(s):

Fourier Transform ◽

Infrared Spectroscopy ◽

Boric Acid ◽

Carbon Fibers ◽

Melt Spinning ◽

Cyclization Reaction ◽

Retardation Effect ◽

Temperature Stabilization ◽

Potential Applications ◽

Acid Nature

AbstractA retardation effect of boric acid on the cyclization reaction of polyacrylonitrile (PAN) was clearly observed by Fourier transform infrared spectroscopy. The Lewis acid nature of boric acid probably accounts for this retardation effect. A quantitative evaluation of this effect was also made, indicating two potential applications, i.e., high temperature stabilization and melt spinning, which are favourable for the cheap and fast fabrication of PAN-based carbon fibers.

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Preparation and Characterization of Porous Si/Carbon Fibers

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.123-125.1087 ◽

2010 ◽

Vol 123-125 ◽

pp. 1087-1090

Author(s):

Ki Ho Jung ◽

Soo Jin Park

Keyword(s):

Carbon Fibers ◽

Reversible Capacity ◽

Accessible Surface Area ◽

Cycling Performance ◽

Porous Si ◽

Electrochemical Behaviors ◽

Potential Applications ◽

Wrinkled Surface ◽

Accessible Surface ◽

Uniform Diameter

In this work, poly(amide imide) (PAI) fibers containing various silicon content ratios were prepared for the precursor of carbon fibers by electrospinning method from 25 wt.% PAI in dimethylformamide (DMF) solution. The fibers were stabilized and then subsequently carbonized in a flow of nitrogen to obtain porous Si/carbon fibers. The morphologies and the crystalline structures of the Si/CFs were characterized by scanning electron microscopy (SEM) and X-ray diffractometer (XRD). The electrochemical behaviors of the Si/CFs were observed by cyclic voltammetry tests. The experimental results indicated that the Si/CFs exhibited convoluted structure and wrinkled surface morphology. The silicon particles had a uniform diameter of approximately 1 μm. And the electrochemical activity of the Si/CFs was gradually improved due to the buffering effect of the large Si volume expansion and shrinkage. In addition, the fibers exhibited large accessible surface area, high reversible capacity, and relatively good cycling performance at high current densities. Consequently, it was found that the introduction of silica could affect the electrochemical properties of the CFs, and the Si/CFs might have potential applications for various fields of electrochemical materials.

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An in situ and ex situ TEM study of the formation of thin cobalt silicide films by molecular beam epitaxy on the silicon (100) surface

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010010648x ◽

1988 ◽

Vol 46 ◽

pp. 884-885

Author(s):

D. Loretto ◽

J. M. Gibson ◽

S. M. Yalisove ◽

R. T. Tung

Keyword(s):

Molecular Beam Epitaxy ◽

Molecular Beam ◽

Defect Density ◽

High Vacuum ◽

Ultra High Vacuum ◽

Ex Situ ◽

Metal Base ◽

In Situ Experiments ◽

Potential Applications

The cobalt disilicide/silicon system has potential applications as a metal-base and as a permeable-base transistor. Although thin, low defect density, films of CoSi2 on Si(111) have been successfully grown, there are reasons to believe that Si(100)/CoSi2 may be better suited to the transmission of electrons at the silicon/silicide interface than Si(111)/CoSi2. A TEM study of the formation of CoSi2 on Si(100) is therefore being conducted. We have previously reported TEM observations on Si(111)/CoSi2 grown both in situ, in an ultra high vacuum (UHV) TEM and ex situ, in a conventional Molecular Beam Epitaxy system.The procedures used for the MBE growth have been described elsewhere. In situ experiments were performed in a JEOL 200CX electron microscope, extensively modified to give a vacuum of better than 10-9 T in the specimen region and the capacity to do in situ sample heating and deposition. Cobalt was deposited onto clean Si(100) samples by thermal evaporation from cobalt-coated Ta filaments.

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Microstructure of laser-irradiated, conducting Kapton polyimide

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100138889 ◽

1995 ◽

Vol 53 ◽

pp. 502-503

Author(s):

D. L. Callahan ◽

Z. Ball ◽

H. M. Phillips ◽

R. Sauerbrey

Keyword(s):

Electron Microscopy ◽

Phase Transition ◽

Transmission Electron Microscopy ◽

Cross Section ◽

Film Surface ◽

Cross Sectional ◽

General Utility ◽

Transmission Electron ◽

Considerable Debate ◽

Potential Applications

Ultraviolet laser-irradiation can be used to induce an insulator-to-conductor phase transition on the surface of Kapton polyimide. Such structures have potential applications as resistors or conductors for VLSI applications as well as general utility electrodes. Although the percolative nature of the phase transformation has been well-established, there has been little definitive work on the mechanism or extent of transformation. In particular, there has been considerable debate about whether or not the transition is primarily photothermal in nature, as we propose, or photochemical. In this study, cross-sectional optical microscopy and transmission electron microscopy are utilized to characterize the nature of microstructural changes associated with the laser-induced pyrolysis of polyimide.Laser-modified polyimide samples initially 12 μm thick were prepared in cross-section by standard ultramicrotomy. Resulting contraction in parallel to the film surface has led to distortions in apparent magnification. The scale bars shown are calibrated for the direction normal to the film surface only.

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EXELFS Studies of Carbon Fibers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100133953 ◽

1990 ◽

Vol 48 (2) ◽

pp. 72-73

Author(s):

V. Serin ◽

K. Hssein ◽

G. Zanchi ◽

J. Sévely

Keyword(s):

Carbon Fibers ◽

Energy Analysis ◽

Electron Excitation ◽

Complex Structures ◽

High Modulus ◽

Promising Technique ◽

X Ray ◽

Fine Structures ◽

X Ray Absorption

The present developments of electron energy analysis in the microscopes by E.E.L.S. allow an accurate recording of the spectra and of their different complex structures associated with the inner shell electron excitation by the incident electrons (1). Among these structures, the Extended Energy Loss Fine Structures (EXELFS) are of particular interest. They are equivalent to the well known EXAFS oscillations in X-ray absorption spectroscopy. Due to the EELS characteristic, the Fourier analysis of EXELFS oscillations appears as a promising technique for the characterization of composite materials, the major constituents of which are low Z elements. Using EXELFS, we have developed a microstructural study of carbon fibers. This analysis concerns the carbon K edge, which appears in the spectra at 285 eV. The purpose of the paper is to compare the local short range order, determined by this way in the case of Courtauld HTS and P100 ex-polyacrylonitrile carbon fibers, which are high tensile strength (HTS) and high modulus (HM) fibers respectively.

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