Surface Modification Of Carbon Fiber Research Articles

Increase of composite structures strength by carbon fiber surface modification with spray deposited carbon nanotubes

The possibility of carbon fiber and the polymer matrix interfacial interface improvement by modification carbon fiber surface with functionalized carbon nanotubes. Nanotubes were deposited to carbon fiber surface by aerosol spray deposition, to increase the tensile strength of composite structures. The relationship between the tensile strength of the composite structure with the epoxy matrix and the uniformity of carbon nanotube coating was investigated.

Effect of carbon fiber surface modification on their interfacial interaction with polysulfone

Polysulfone-based composites reinforced with carbon fibers (CF) were obtained by the polymer solution impregnation method. The effect of carbon fibers surface modification on the fiber-matrix interaction in the composites was studied. It was found that thermal oxidation has a strong effect on the chemical composition and functional groups on the carbon fibers surface. The X-ray photoelectron spectroscopy showed that the surface modification at temperatures up to 500 °C results in the formation of hydroxyl COH, ethereal COC, carboxyl COOH, carbonyl CO and epoxy groups on the CF surface. A considerable increase in the interlaminar shear strength of the composites reinforced with modified fibers was observed.

Functionalization with MXene (Ti3C2) Enhances the Wettability and Shear Strength of Carbon Fiber-Epoxy Composites

MXene is a two-dimensional transition metal carbide or carbonitride with graphene-like 2D morphology and high surface activity, which are useful features in energy storage, catalysis, and adsorption. However, only a handful of structural applications have so far been reported. In this study, functionalization of a carbon fiber (CF) was achieved by MXene (Ti3C2) to improve the CF surface wettability. The results showed that functionalization of MXene not only changed the CF surface topography and increased the mechanical engagement effect during debonding but also enhanced the surface activity of carbon fibers. The interfacial shear strength increased by 186% when compared with nonfunctionalized specimens. A possible interfacial enhancement mechanism was proposed to provide a future roadmap for surface modification of carbon fibers.

Building the silicon carbide nanowire network on the surface of carbon fibers: Enhanced interfacial adhesion and high-performance wear resistance

In order to improve the tribological properties of carbon fiber (CF) reinforced resin matrix composites (CFRRMC), in-situ grown silicon carbide nanowires (SiCnws) were established on the surface of CF. The contact angle of the modified CF with the resin was reduced by 32° compared to the original. The grafted SiCnws could bridge the CF and resin and form a network on the surface of CFRRMC, greatly improving their interfacial bonding and effectively transferring loads. More importantly, the SiCnws-CFRRMC has the better stability of coefficient of friction. Further, the wear rate of SiCnws-CFRRMC is significantly reduced by 76%, which is attributed to the formation of friction film and reduced fatigue wear. This work enriches the approach to surface modification of CF and provides an effective way to obtain high-performance materials by building networks, extending the applications of CFRRMC.

Surface Modification of Carbon Fiber Interlayer Via Amide Coupling Reaction for High-Performance Lithium-Sulfur Batteries: Experimental and Theoretical Investigation

Lithium-sulfur battery (LSB) is a promising candidate as a conventional lithium-ion battery replacement due to its high theoretical specific capacity and high energy density together with additional advantages of low cost, abundance, and environment friendliness. However, LSB still suffers from many issues including natural insulator of active sulfur and final product of Li2S, polysulfide shuttle effect, and 80% volume expansion during cycling which are causes of capacity fading in the LSB. To fix the mentioned issues as well as improve performances of LSB, carbon interlayer has introduced between a sulfur cathode and separator to suppress lithium polysulfide diffusion and act as an upper current collector. Here, we prepare surface modified carbon fiber paper (CFP) via a simple amide coupling reaction with various amine reactants to study the effect of functional groups on the surface of the CFP on LSB performances. LSB with modified CFPs as interlayers show significant higher specific capacity than LSB without interlayer due to the chemisorption ability between functional groups on the CFP surfaces and lithium polysulfide intermediates. The LSB with modified CFP by 4-aminobenzoic acid interlayer exhibits the highest specific capacity along with long cyclability observed from high capacity retention of 88.5% and Coulombic efficiency above 98% after 200 cycles. Furthermore, the lithium polysulfide chemisorption capabilities of each functional group are fundamentally explained via density functional theory (DFT) calculations through the binding energy between functional groups and polysulfide intermediates. More interestingly, we also prove that the excellent performance of the LSB with 4-aminobenzoic acid interlayer is due to the strong lithium bond of S-L…O coupled with hydrogen bond of S…H-O.

Immobilization of N-doped carbon porous networks containing copper nanoparticles on carbon felt fibers for catalytic applications

Applying green techniques and treating organic pollutants efficiently in water can be regarded as one of the biggest challenges in chemistry. In this work, reduction of such environmental pollutants as toxic 4-nitrophenol, methylene blue and rhodamine B by NaBH4 was studied at room temperature using a series of surface modified carbon fiber felts with Cu(x wt%, x = 1.5, 3.0, 5.0) nanoparticles buried in a nitrogen-doped carbon porous network. The catalyst, referred to as Cu(x wt%)/N-CF, was prepared by the pyrolysis of carbon fiber felts containing different amounts of the Cu(salen) complex at 650 °C for 2 h under argon atmosphere. The most efficient catalyst showing a high performance and recyclability could also be applied industrially for wastewater treatment due to its bulk structure. The catalytic efficiency of the synthesized composites was attributed to the high distribution of copper nanoparticles in the matrix of the modified carbon fibers felt. In the optimum conditions, Cu(1.5 wt%)/N-CF exhibited the highest rate constant, k = 0.045 s−1 and TOF = 23.7 h−1, at room temperature for reducing 4-nitrophenol to 4-aminophenol; this was significant in comparison with the expensive metal–based nanocatalysts. This reduction reaction, due to the large potential difference between BH4− as the donor and 4-nitrophenol as the acceptor, faces a large kinetic barrier and did not occur without the catalyst. Therefore, this composite could be an ideal platform for use as a sustainable and green heterogeneous catalyst in many chemical processes and wastewater treatments.

Mechanical behavior of Graphene decorated carbon fiber reinforced polymer composites: An assessment of the influence of functional groups

Decoration of the Carbon fiber (CF) surface using graphene based nano-fillers (GBN) by the electrophoretic deposition (EPD) is possibly one of the most emerging techniques for the enhancement of the mechanical response of carbon fiber reinforced polymer (CFRP) composites. Present investigation is focused on enhancing the flexural and interlaminar properties of a CFRP composite by surface modification of carbon fiber by EPD technique using GBN (graphene (G), graphene oxide (G-O), graphene hydroxyl (G-OH) and graphene carboxyl (G-COOH)). The highest flexural strength and interlaminar shear strength was obtained for the G-COOH modified CFRP composite, which are 9.6% and 22.9% higher than that of control CFRP respectively. Dynamic mechanical thermal analysis (DMTA) was conducted in the temperature range of 30 °C to 180 °C to understand the temperature dependent mechanical behavior of all the composites. In addition, fractographic analysis was carried out using scanning electron microscopy (SEM) to understand various failure micro-mechanisms.

Effect of Carbon Fiber Surface Modification on the Mechanical Properties of Carbon-Fiber-Reinforced Ultrahigh-Molecular-Weight Polyethylene Composite

In this paper, the surface properties and morphologies of the concentrated nitric acid (HNO3)-modified carbon fiber (CF) were characterized by XPS, SEM, and contact angle goniometer, respectively. The results showed that both the oxygen-containing functional groups content and the surface roughness of concentrated HNO3-modified CF significantly increased. The contact angle of concentrated HNO3-modified CF was obviously lower than that of unmodified CF. Studies on the mechanical properties of carbon-fiber-reinforced ultrahigh-molecular-weight polyethylene (CF/UHMWPE) composite revealed that the stress–strain behavior gradually changed from nonlinear to linear relationship with the rise of CF content in UHMWPE matrix. Both the tensile strength and modulus increased with the rise of CF content. Conversely, as the CF content in UHMWPE matrix is increasing, the flexural strength and modulus increased first and then decreased. The flexural strength and modulus of CF/UHMWPE composite with 30 wt.% CF content reached the maximum value of 157.61 MPa and 9.82 GPa, respectively. Moreover, the CF surface modification and CF content have a synergistic effect on the tensile and flexural mechanical properties of the CF/UHMWPE composite. The influence of CF modification on the tensile and flexural mechanical properties of the composite became more and more obvious with the rise of CF content.

Surface Modification of Carbon Fibers by Grafting PEEK-NH2 for Improving Interfacial Adhesion with Polyetheretherketone.

Due to the non-polar nature and low wettability of carbon fibers (CFs), the interfacial adhesion between CFs and the polyetheretherketone (PEEK) matrix is poor, and this has negative effects on the mechanical properties of CF/PEEK composites. In this work, we established a modification method to improve the interface between CFs and PEEK based chemical grafting of aminated polyetheretherketone (PEEK-NH2) on CFs to create an interfacial layer which has competency with the PEEK matrix. The changed chemical composition, surface morphology, surface energy, and interlaminar shear strength were investigated. After grafting, the interlaminar shear strength (ILSS) was improved by 33.4% due to the covalent bonds in the interface region, as well as having good compatibility between the interface modifier and PEEK. Finally, Dynamic Mechanical Analysis (DMA) and Scanning Electron Microscopy (SEM) observation also confirmed that the properties of the modified CF/PEEK composites interface were enhanced. This work is, therefore, a beneficial approach towards enhancing the mechanical properties of thermoplastic composites by controlling the interface between CFs and the PEEK matrix.

Carbon fiber surface modification for tailored fiber-matrix adhesion in the manufacture of C/C-SiC composites

The surface of a commercial PAN-based carbon fiber (CF) was modified to optimize fiber–matrix adhesion (FMA) in a CF-reinforced polymer (CFRP) preform used for the manufacture of CF-reinforced silicon carbide (C/C-SiC) composites. For these purposes, CFs were thermally desized and then electrochemically oxidized. The surface of the fibers was investigated by atomic-force microscopy. The CFs’ chemical composition, specific surface acidity and wettability were investigated by different analytical methods. CFRPs based on electrochemically oxidized and untreated CFs were subsequently carbonized and transformed into C/C-SiC via liquid silicon infiltration (LSI). The microstructure of the composites was investigated by scanning electron microscopy (SEM). Single-fiber push-out tests were used to characterize FMA and revealed the highest interfacial fracture toughness for the CFRP based on electrochemically oxidized CFs. The surface treatment also showed positive effects after siliconization, e.g., a lower conversion rate of the CFs and improved mechanical properties.

Immobilization of Enterobacter aerogenes on carbon fiber and activated carbon to study hydrogen production enhancement

Hydrogen production by immobilized Enterobacter aerogenes on the carbon fiber (CF), surface modified carbon fiber, granular and powdered activated carbon in batch mode of operation was investigated. The surface morphology and chemical properties of CFs were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). Among the supports employed, immobilization on treated CF (CF-T) resulted in increase of both hydrogen production rate (HPR) and hydrogen yield (HY). The present study showed that immobilized E. aerogenes on 0.2 mg/mL CF-T resulted in HY of 2.56 mol/mol glucose and HPR of 2.48 L/L.h representing 23%, and 34%, enhancement compared to the free E. aerogenes, respectively. Using powdered activated carbon as immobilization support resulted in HY of 2.13 mol/mol glucose, which was higher in comparison to HY of granular activated carbon by 1.33 mol/mol glucose.

Lignin as a Functional Green Coating on Carbon Fiber Surface to Improve Interfacial Adhesion in Carbon Fiber Reinforced Polymers.

While intensive efforts are made to prepare carbon fiber reinforced plastics from renewable sources, less emphasis is directed towards elaborating green approaches for carbon fiber surface modification to improve the interfacial adhesion in these composites. In this study, we covalently attach lignin, a renewable feedstock, to a graphitic surface for the first time. The covalent bond is established via aromatic anchoring groups with amine functions taking part in a nucleophilic displacement reaction with a tosylated lignin derivative. The successful grafting procedures were confirmed by cyclic voltammetry, X-ray photoelectron spectroscopy, and field emission scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. Both fragmentation and microdroplet tests were conducted to evaluate the interfacial shear strength of lignin coated carbon fiber samples embedded in a green cellulose propionate matrix and in a commercially used epoxy resin. The microdroplet test showed ~27% and ~65% increases in interfacial shear strength for the epoxy and cellulose propionate matrix, respectively. For the epoxy matrix covalent bond, it is expected to form with lignin, while for the cellulosic matrix hydrogen bond formation might take place; furthermore, plastisizing effects are also considered. Our study opens the gates for utilizing lignin coating to improve the shear tolerance of innovative composites.

High performance wire-type supercapacitor with Ppy/CNT-ionic liquid/AuNP/carbon fiber electrode and ionic liquid based electrolyte

We report a fabrication of a high-performance wire-type supercapacitor through surface modification of carbon fiber with ionic liquid, nanomaterials, and gel electrolyte containing ionic liquid. Coating of Au nanoparticles onto carbon fiber increases both surface area and electrical conductivity. Dip-coating of mixture of ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]), carbon nanotubes, and electropolymerization of polypyrrole (Ppy) onto Au coated fiber for pseudocapacitance results in high capacitance. The use of propylene carbonate-poly(methyl methacrylate)-[EMIM][TFSI] gel electrolyte gives high operation voltage. Such wire-type supercapacitor exhibits a high voltage of 2.5 V, an areal capacitance of 38.49 mF cm−2, and a maximum energy and power density of 24.7 μWh cm−2 and 3.52 mW cm−2, respectively. In addition, the cyclic stability of the supercapacitor is dramatically enhanced by using 2-naphthalene sulfonic acid as a dopant in electropolymerization of Ppy. Encapsulation with a thermally shrinkable tube endows the supercapacitor with mechanical stability and waterproof features when it is bent, folded, twisted, even in water. This work demonstrates high potential of such wire-type supercapacitor as a flexible energy-storage device for various applications, especially those that require high voltage.

The surface modification of carbon fiber for thermoplastic HDPE composites

The interfacial adhesion strength between the fiber and the matrix greatly affects the properties of the carbon fiber (CF)–reinforced composite. The presence of surface functional groups on the fiber and changes in surface roughness were determined by X‐ray photoelectron spectroscopy, scanning electron microscopy (SEM), and Raman spectroscopy. The effect of surface modification of CF on the mechanical properties and tribological properties of the composites is enhanced. The performance has been significantly improved. SEM analysis showed that modification had a positive effect on the interface between fiber and matrix. In the paper, the method of CF modification and the treatment of enhanced high‐density polyethylene have simple and effective characteristics, which can be widely used and have guiding significance for industrial production.

Selective oxidation of carbon to enhance both tensile strength and interfacial adhesion of carbon fiber

ABSTRACT Among the various techniques utilized for surface modification of carbon fiber, the most practical one for commercial production is anodization due to its controllable oxidation level in a continuous process. During the traditional process, the adhesion between the fiber and epoxy resin can be improved, but at the expense of reducing tensile strength. Here, we present a novel anodic oxidation method, i.e., the carbon atoms on the ridges are selectively oxidized and those in the grooves remain intact. In this way, the longitudinal grooves on the fiber surface become shallow and the tensile strength of fiber shows an obvious increase by comparison with the carbon fiber oxidized via traditional oxidation method. More importantly, due to the high density of oxygen-containing groups on the ridges, the fiber shows great wetting properties and strong adhesion to epoxy resin.

Effect of Tow Size and Interface Interaction on Interfacial Shear Strength Determined by Iosipescu (V-Notch) Testing in Epoxy Resin.

Testing methodologies to accurately quantify interfacial shear strength (IFSS) are essential in order to understand fiber-matrix adhesion. While testing methods at a microscale (single filament fragmentation test—SFFT) and macroscale (Short Beam Shear—SBS) are wide spread, each have their own shortcomings. The Iosipescu (V-notch) tow test offers a mesoscale bridge between the microscale and macroscale whilst providing simple, accurate results with minimal time investment. However, the lack of investigations exploring testing variables has limited the application of Iosipescu testing to only a handful of studies. This paper assesses the effect of carbon fiber tow size within the Iosipescu tow test for epoxy resin. Tow sizes of 3, 6, and 9 k are eminently suitable, while more caution must be shown when examining 12, and 15 k tows. In this work, tows at 18 and 24 k demonstrated failure modes not derived from interfacial failure, but poor fiber wetting. A catalogue of common fracture geometries is discussed as a function of performance for the benefit of future researchers. Finally, a comparison of commercial (T300), amine (T300-Amine), and ethyl ester (T300-Ester) surface modified carbon fibers was conducted. The outcomes of this study showed that the Iosipescu tow test is inherently less sensitive in distinguishing between similar IFSS but provides a more ‘real world’ image of the carbon fiber-epoxy interface in a composite material.

Surface modification of carbon fibers by microwave etching for epoxy resin composite

Microwave irradiation was applied to modify the carbon fibers immersed in water. The surface chemical composition and morphology of treated carbon fibers were investigated in detail. It showed that great numbers of oxygen-containing groups were introduced in treated carbon fiber surfaces and nitrogen heterocyclic rings of carbon fiber bulk exposed for the exfoliation of surface layers. The surface roughness of carbon fibers was enlarged by oxidative etching of microplasma excited by microwave irradiation, and some nano humps were formed on carbon fiber surfaces. Although the tensile strength of treated carbon fibers were slightly deteriorated, the interfacial shear strength of treated carbon fibers/epoxy resin composite, as compared with that of untreated carbon fibers/epoxy resin composite, was significantly enhanced. The modification mechanism is that the microplasma and the exfoliation of monolayer graphene oxide sheets lead to the variations of chemical structure and physical morphology in carbon fiber surfaces.

Surface modification of carbon fiber support by ferrous oxalate for biofilm wastewater treatment system

Abstract In order to overcome the shortcoming of poor hydrophilicity and smooth surface of carbon fiber, and to improve water treatment effect of biofilm system using carbon fiber as support, this paper employed nitric acid and ferrous oxalate to modify carbon fiber. A series tests were conducted on untreated carbon fiber, nitric acid oxidized carbon fiber, nitric acid and ferrous oxalate modified carbon fiber, namely, scanning electron microscopy-energy dispersive spectrometer, X-ray photoelectron spectroscopy, static contact angle and water treatment effect. Results showed that, hydrophilic functional group containing oxygen and nitrogen on the surface of carbon fiber increased after modification by nitric acid and ferrous oxalate, which greatly improved the hydrophilicity of carbon fiber surface. The ferrum element in ferrous oxalate modified carbon fiber existed in the form of magnetic oxide (Fe3O4) via Fe O C to bond with carbon fiber, which noticeably enhanced the surface roughness of carbon fiber. Dry weight of biofilm per unit immobilized on ferrous oxalate modified carbon fiber support enhanced and it was 2.3 and 0.6 times bigger than that of untreated and nitric acid oxidized carbon fiber. Biofilm system with ferrous oxalate modified carbon fiber as support had better water treatment effect and stable effluent standard. The average removal efficiency of chemical oxygen demand, ammonia nitrogen and total phosphorus achieved 97%, 96% and 97%. In addition, removal efficiency of chemical oxygen demand, ammonia nitrogen and total phosphorus increased by 7.18%, 10.30%, 9.40% and 4.86%, 4.30%, 6.40%, compared to carbon fiber and nitric acid oxidized carbon fiber support biofilm system. Combination of nitric acid oxidation and ferrous oxalate deposition, which has never been developed before, is a promising carbon fiber surface modification method to improve its performance as biofilm support.

Improving the interfacial property of carbon fiber/PI resin composite by grafting modification of carbon fiber surface

The poor interfacial adhesion between carbon fibers (CFs) and polyimide (PI) resin has seriously hampered the application of CF/PI composites. In this work, the interfacial adhesion was efficiently enhanced by grafting on the CF surface. Surface morphology and surface composition of modified carbon fibers were characterized, which indicated that acrylamide was grafted successfully on the CF surface and the surface roughness was increased slightly. After grafting, the interface shear strength of modified carbon fibers/PI composites was significantly improved by 86.96%, and the interlaminar shear strength was enhanced by 55.61% due to the covalent bonds in interphase and the toughening effect of sizing agent. Moreover, the mechanical properties of composites with different interfacial adhesion were measured, which further confirmed the effect of the grafting modification.

Synergistic interfacial effects of ionic liquids as sizing agents and surface modified carbon fibers

This paper presents investigations into the use of ionic liquids as sizing agents for carbon fibers in epoxy matrices.