Commercial Carbon Fiber Research Articles

Fracture toughness in SPCC/CFRP hybrid laminates: Mode I and mode II perspectives

Hybrid composites using adhesive joints are gaining popularity in various industries as their various material combinations can create certain advantages. This research focuses on examining the mode I and mode II fracture toughness characteristics of the combined laminate between Steel Plate Cold Rolled Commercial (SPCC) metal and Carbon Fiber Reinforced Polymer (CFRP) composite processed using adhesive bonding. SPCC/CFRP hybrid laminate composites were manufactured with a variety of manufacturing options (A, B, and C) to find the most optimal method using two types of epoxy and cyanoacrylate adhesives, with two different bonding processes: secondary bonding and co-bonding. Fracture toughness values were measured through the Double Cantilever Beam (DCB) test for mode I and the End Notched Flexure (ENF) test for mode II. The test results showed that epoxy adhesives in the SPCC/CFRP adhesive joints provided better fracture toughness performance, especially when combined with the co-bonding technique. Specimens from manufacturing option C showed the highest GIC and GIIC values of 83.05 and 254.94 J/m2, respectively. These values increased by 58.98 % and 80.48 % compared to manufacturing options A and B in Mode I. Additionally, the GIIC value for manufacturing option C increased by 78.00 % and 66.76 % compared to manufacturing options A and B. The SPCC/CFRP hybrid laminates showed adhesive failure on the SPCC surface when using epoxy adhesive, whereas adhesive failure occurred on the CFRP surface with cyanoacrylate adhesive for the different manufacturing options.

Efficient Multifunctional Modification of Commercial Carbon Fiber through Tailored Carbon Layer Structure

Polyacrylonitrile-based commercial carbon fibers (CFs) have garnered significant attention in mechanical applications because of their exceptional mechanical properties. However, their functional versatility relies heavily on the structural intricacies of duplex carbon layers. Current modification approaches, though effective, are encumbered by complexity and cost, limiting widespread adoption across diverse fields. We herein present a straightforward modification strategy centered on regulating carbon layers to unlock the multifunctional potential of CFs. Our method leverages two common anions, Cl− and SO42−, to facilitate oxidation reactions in CFs under robust alkali and high voltage conditions. Cl− effectively activates carbon layers, while SO42− facilitates layer movement. The electrocatalytic activities of the resultant CFs are enhanced, with state-of-the-art performance as supercapacitors and exceptional stability. Moreover, our approach achieves a groundbreaking milestone by bending and fusing CFs without using binders. This breakthrough can reduce the manufacturing costs of CF-based products. It also facilitates the development of novel microelectronic devices.

Constructing Mechanochromic Fluorescent Interphase via Core-Shell Microcapsules: A Route for Interface Reinforcing and Damage Self-Reporting of CFRP Composites.

Perylenediimide-chitosan/γ-poly (glutamic acid) microcapsules sizing (PDI-CS/γ-PGA) core-shell microcapsule is designed and used to establish a novel interphase in carbon fiber/epoxy (CF/EP) composite, and the interfacial property, as well as the damage self-reporting of the composite, is compared with desized carbon fiber (CF-desized)/EP and commercial carbon fiber (CF-COM)/EP composite. The ruptured PDI-CS/γ-PGA microcapsule exhibits strong "turn-on" green fluorescence from the released PDI upon mechanical stimuli. The anchoring of PDI-CS/γ-PGA microcapsule on carbon fiber with PDI-CS/γ-PGA microcapsules sizing (CF@PDI-CS/γ-PGA) surface results in increased chemical activity and roughness, exhibiting a weak green fluorescence signal instead of non-fluorescence on CF-desized and CF-COM surface. The transverse fiber bundle tensile (TFBT) strength of CF@PDI-CS/γ-PGA composite is 80.97% and 31.09% higher than those of CF-desized/EP and CF-COM/EP composite, which is attributed to the mechanical interlocking and chemical bonding interaction between carbon fiber and epoxy matrix by introducing PDI-CS/γ-PGA microcapsule with spherular structure and active groups. After microdroplet testing, the strong "turn-on" green fluorescence signal of the released PDI from the microcapsules is detected in the interfacial debonding regions, realizing the microscopic damage self-reporting of CF@PDI-CS/γ-PGA composite.

Commercial Carbon Fibers as Host for Sodium Deposition to Achieve High Volumetric Capacity

Commercial Carbon Fibers as Host for Sodium Deposition to Achieve High Volumetric Capacity

Electrosynthesis of Ammonia from Nitrate Using a Self-Activated Carbon Fiber Paper.

While electrochemically upcycling nitrate wastes to valuable ammonia is considered a very promising pathway for tackling the environmental and energy challenges underlying the nitrogen cycle, the effective catalysts involved are mainly limited to metal-based materials. Here, we report that commercial carbon fiber paper, which is a classical current collector and is typically assumed to be electrochemically inert, can be significantly activated during the reaction. As a result, it shows a high NH3 Faradaic efficiency of 87.39% at an industrial-level current density of 300 mA cm-2 for over 90 h of continuous operation, with a NH3 production rate of as high as 1.22 mmol cm-2 h-1. Through experimental and theoretical analysis, the in situ-formed oxygen functional groups are demonstrated to be responsible for the NO3RR performance. Among them, the C-O-C group is finally identified as the active center, which lowers the thermodynamic energy barrier and simultaneously improves the hydrogenation kinetics. Moreover, high-purity NH4Cl and NH3·H2O were obtained by coupling the NO3RR with an air-stripping approach, providing an effective way for converting nitrate waste into high-value-added NH3 products.

Self‐emulsifying anionic polyester sizing agents for enhancing the interfacial and mechanical properties of carbon fiber/vinyl ester resin composites

AbstractWith the increasing emphasis on environmental protection, there is a growing focus on the synthesis of water‐solvent self‐emulsifying sizing agents. In this study, five types of anionic polyester sizing agents with varying molecular weights were synthesized to explore the effect of molecular weight on the interfacial bonding strength of carbon fiber (CF) reinforced vinyl resin composites. The results demonstrated that the molecular weights of the synthesized sizing agents were precise; the particles in the sizing agents were nanometer‐sized, monodisperse, and exhibited high thermal stability. When the molecular weight was 8000, it exhibited optimal wettability for CF, leading to a substantial improvement in the interlaminar shear strength, reaching 71.8 MPa, which represents a significant increase of 22.7% compared with commercial CFs (CFF). Additionally, the interfacial shear strength was maximized at 13.23 MPa, which was significantly increased by 14.2% compared with CCF. These significant improvements in surface properties and mechanical performance were attributed to the excellent wettability of the CF surface, effective spreading performance of the sizing agent, the presence of double bonds in the sizing agent facilitating reactions with free radicals on the CF surface, and the residual double bonds further undergoing curing with the vinyl resin, promoting the reinforcement of interface bonding.

Highly Sensitive and Stable Flexible Smart Sensors Based on Commercial Carbon Fiber Powder Inks.

With the fast development of the smart lifestyle in recent years, simple and flexible body condition monitoring has become more and more important. However, currently, commercially available motion-sensing devices always lack flexibility or at a high cost. This article has fully explored the merits of a commercial and easily available material of carbon fiber powder (CFP) and prepared CFP-based screen printing inks. This conductive ink can be directly and quickly printed onto a variety of different flexible common substrates, such as paper, cotton fabrics, etc., to prepare flexible sensors. At the same time, as a result of the good photothermal performance and conductivity of CFP, the printed flexible sensors have fast and stable performance on thermal and human motion detection. The use of CFP as the smart element to construct a wearable device will offer a choice for the intelligent industry.

Constructing a Novel Moderately Modulus "Rigid-Flexible" Structure with Synergistic Reinforcement on the Carbon Fiber Surface to Enhance the Mechanical Properties of Carbon Fiber/Epoxy Composites at Elevated Temperatures.

To improve the mechanical performance of carbon fiber (CF)/epoxy composites in high-temperature environments, a moderately modulus gradient modulus interlayer was constructed at the interface phase region of composites. This involved the design of a "rigid-flexible" synergistic reinforcement structure, incorporating rigid nanoparticle GO@CNTs and a flexible polymer polynaphthyl ether nitrile ketone onto the CF surface. Notably, at 180 °C, compared to commercial CF composites, the CF-GO@CNTs-PPENK composites displayed a remarkable improvement in their mechanical characteristics (interfacial shear, interlaminar shear, flexural strength, and modulus), achieving enhancements of 173.0, 91.5, 225.7, and 376.4%, respectively. The principal reason for this the moderately modulus interface phase composed of GO@CNTs-PPENK (where GO and CNTs predominantly consist of carbon atoms with sp2-hybridized orbitals, forming highly stable C-C structures, while PPENK possesses a "twisted non-coplanar" structure), which exhibited resistance to deformation at high temperatures. Moreover, it greatly improved the mechanical interlocking, wettability, and chemical compatibility between CF and the epoxy. It also played a crucial role in balancing and buffering the modulus disparity. The interface failure behavior and reinforcement mechanisms of the CF composites were analyzed. Furthermore, validation of the presence of a moderately modulus gradient interlayer at the interface phase region of CF-GO@CNTs-PPENK composites was performed by using atomic force microscopy. This study has established a theoretical foundation for the development of high-performance CF composites for use in high-temperature fields.

Effect of polyphenylene sulfide sulfone sizing agent on interfacial, thermal, and mechanical properties of carbon fiber

AbstractPolyphenylene sulfide sulfone (PPSS) was synthesized by one‐step method and utilized as a sizing agent for carbon fibers. The effects of various monomer ratios, reaction time, and reaction temperature were investigated on the molecular weight of PPSS. The thermal analysis revealed that the product PPSS exhibited a glass transition temperature exceeding 215.5°C, indicating exceptional thermal stability. After PPSS sizing treatment, the grooves on the surface of carbon fibers were filled, resulting in a substantial enhancement of the microinterface properties. The surface energy was increased by 8.2%, while the maximum weight loss temperature was 27.8% higher than that of the commercial carbon fiber. The tensile strength of the carbon fiber after heat treatment reached 2196 MPa, representing a 45.9% increase over that of the commercial carbon fiber.

Preparation of unsaturated self-emulsifying polyester sizing agents for improving interfacial and mechanical properties of carbon fiber/vinyl ester resin composites

In order to promote the interfacial adhesion between carbon fiber and vinyl ester matrix, a series of unsaturated self-emulsifying anionic polyester sizing agents were designed. The results indicated that the sizing agents exhibited a uniform particle size distribution at the nanometer level and demonstrated favorable thermal stability below 200 °C. As the content of double bonds of sizing agents increases, the glass transition temperature also increases, and the moisture absorption of sized carbon fiber decreases. The carbon fiber surface becomes smoother after sizing. Moreover, the interlaminar shear strength and interfacial shear strength increased by 18.8 % and 43.4 %, respectively, compared to the commercial carbon fiber. This is mainly due to the unsaturated bonds in the sizing agent react with the free radicals on the surface of the carbon fiber, which enhance the interface bonding strength between the sizing agent and the surface of the carbon fiber and the vinyl ester matrix.

The Microstructure and Thermal Conductive Behavior of Three-Dimensional Carbon/Carbon Composites with Ultrahigh Thermal Conductivity.

Carbon-based composite materials, denoted as C/C composites and possessing high thermal conductivity, were synthesized utilizing a three-dimensional (3D) preform methodology. This involved the orthogonal weaving of mesophase pitch-based fibers in an X (Y) direction derived from low-temperature carbonization, and commercial PAN-based carbon fibers in a Z direction. The 3D preforms were saturated with mesophase pitch in their raw state through a hot-pressing process, which was executed under relatively low pressure at a predetermined temperature. Further densification was achieved by successive stages of mesophase pitch impregnation (MPI), followed by impregnation with coal pitch under high pressure (IPI). The microstructure and thermal conductivity of the C/C composites were systematically examined using a suite of analytical techniques, including Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and PLM, amongst others. The findings suggest that the volumetric fraction of fibers and the directional alignment of the mesophase pitch molecules can be enhanced via hot pressing. The high graphitization degree of the mesophase pitch matrix results in an increased microcrystalline size and thus improved thermal conductivity of the C/C composite. Conversely, the orientation of the medium-temperature coal pitch matrix is relatively low, which compensates for the structural inadequacies of the composite material, albeit contributing minimally to the thermal conductivity of the resultant C/C composites. Following several stages of impregnation with mesophase pitch and subsequent impregnation with medium-temperature coal pitch, the 3D C/C composites yielded a density of 1.83 and 2.02 g/cm3. The thermal conductivity in the X (Y) direction was found to be 358 and 400 W/(m·K), respectively.

Mechanical Strength and Surface Analysis of a Composite Made from Recycled Carbon Fibre Obtained via the Pyrolysis Process for Reuse in the Manufacture of New Composites.

This work aims to obtain recycled carbon fibre and develop an application for this new material. The carbon fibres were obtained by recycling aerospace prepreg waste via the pyrolysis process. The recycled fibres were combined with an Araldite LH5052/Aradur LY5053 epoxy resin/hardener system using manual lay-up and vacuum bagging processes. For comparison, the same resin/hardener system was used to produce a composite using commercial carbon fibre. The recycled and commercial composites were subjected to flexural, tensile and Mode I testing. Fracture aspects were analysed via scanning electron microscopy (SEM). The pyrolysis process did not affect the fibre surface as no degradation was observed. The fracture aspect showed a mixture of failure in the recycled composite laminate and interlaminar/translaminar failure near the surface of the commercial composite caused by flexural stress. Flexural and tensile tests showed a loss of mechanical strength due to the recycling process, but the tensile values were twice as high. The sand ladder platform was the project chosen for the development of a product made with recycled carbon fibres. The product was manufactured using the same manufacturing process as the specimens and tested with a 1243 kg car. The method chosen to design, manufacture and test the prototype sand ladder platform made of recycled carbon fibre was appropriate and gave satisfactory results in terms of high mechanical strength to bending and ease of use.

Transformation of traditional carbon fibers from microwaves reflection to efficient absorption via carbon fiber microstructure modulation

The high conductivity of commercial carbon fibers leads to a noticeable skinning effect and weak microwave impedance matching. This results in insufficient effective absorption bandwidth and less than ideal overall wave absorption performance, mainly reflecting electromagnetic waves. These limitations restrict the application of carbon fibers. In this study, we successfully prepared carbon fiber/epoxy composites with adjustable electrical conductivity by precisely controlling the temperature and time of pre-oxidized polyacrylonitrile (PAN) fibers during the low-temperature carbonization stage. This allowed us to regulate the components and microstructure of conductive carbon fibers. The carbon fiber/epoxy composites demonstrated exceptional microwave absorption performance due to their various loss mechanisms. The impedance matching conditions and microwave attenuation capability were also quantitatively evaluated. For 850-9 samples, an effective bandwidth of approximately 7 GHz (11 GHz–18 GHz) was achieved with a thickness of 2.5 mm. For 900-9 samples, the best reflection loss achieved is −39.9 dB at 5.8 GHz, which corresponds to a thickness of 3 mm. The carbon fibers with different electrical conductivity can be obtained by modulating the microstructure of carbon fibers, which can improve the impedance matching performance of conductive carbon fibers and reduce their reflection of electromagnetic waves to improve the microwave absorption performance, achieving the transformation of traditional carbon fibers from electromagnetic shielding to effective microwave absorption. This simple and efficient preparation method has yielded promising results and offers a new avenue for the advancement of high-performance carbon fiber microwave absorbing materials.

Facial synthesis of FeOOH array-anchored carbon fiber as flow-through chloride-capturing electrode for ultrafast and super-stable capacitive deionization

Faradic-based capacitive deionization (FDI) has been recognized as one of the most promising technologies to solve the freshwater crisis, yet was plagued by two most serious issues, i.e., slow desalination kinetics and poor cyclic stability. Herein, an ultrafast and super-stable FDI system is successfully developed based on the employment of a pseudocapacitive material as flow-through chloride-capturing electrode. While the pseudocapacitive material, anchoring FeOOH arrays on the surface of commercial carbon fiber cloth (CF@FeOOH) ensures high desalination durability by preventing possible FeOOH aggregation through the carbon fiber framework, the unique flow-through electrode enables fast mass transfer by channeling the feed stream inside its microchannels. Consequently, the FDI system equipped with flow-through CF@FeOOH electrodes displays an excellent desalination rate of 0.48 mg g−1 s−1 with ultra-robust cyclic stability (no reduction after 60 cycles and only 14.9 % capacity reduction after 150 cycles), while maintaining its high desalination capacity of 52.04 mg g−1, exemplifying the critical importance of both delicate material design and rational cell architecture.

Prestoring lithium in a 3D carbon fiber cloth coated with MOF-derived MnO for composite lithium anodes with high areal capacity and current density

We propose a facile design utilizing a commercial carbon fiber cloth (CFC) coated with metal–organic-framework-derived MnO nanoparticles as a 3D host for prestoring molten lithium and successfully fabricate a CFC@MnO@Li composite anode.

Reinforcement Effect of Recycled CFRP on Cement-Based Composites: With a Comparison to Commercial Carbon Fiber Powder

Reinforcement Effect of Recycled CFRP on Cement-Based Composites: With a Comparison to Commercial Carbon Fiber Powder

Enhanced transverse strength of 3D printed acrylonitrile butadiene styrene parts by carbon fiber/epoxy pin insertion

Thermoplastic parts fabricated by material extrusion (MEX) 3D printing usually possess weak inter-layer bonding, leading to low mechanical performance in the Z-direction. Here, we develop a simple but effective post-treatment method to improve the Z-strength of MEX-printed acrylonitrile butadiene styrene (ABS) parts. In this method, commercial carbon fiber (CF) tows and epoxy were embedded into internal channels in MEX-printed structures to form high-strength CF/epoxy pins. Due to the mechanical interlock between the CF/epoxy pins and the printed ABS, the Z-strength of the printed parts improved significantly. Specifically, the Z-pinned ABS samples exhibit a strength of up to 71.74 MPa and a Young’s modulus of up to 5.93 GPa in the transverse direction, which were 335 % and 266 % higher than those of the printed neat counterparts, respectively. We find that the mechanical performance of the Z-pinned samples follows a simple rule of mixtures which is able to capture the Z-dependent mechanical strength and Young’s modulus. Also, curved CF/epoxy pins were successfully formed within printed thin-walled curved structures, offering the capability to strengthen MEX printed structures with complex shapes. This work demonstrates that the Z-pin embedding process can be an effective approach to improve the transverse strength of the MEX printed parts for load-bearing structural applications.

High temperature oxidation of additively manufactured silicon carbide/carbon fiber nanocomposites

An additive manufacturing process and subsequent pyrolysis cycle were used to fabricate SiC matrix/carbon fiber hybrid composites. The matrix was fabricated using a mixture of preceramic polymer and acrylate monomers, while polyacrylonitrile (PAN) precursor was used to fabricate fibers via electrospinning. The precursor matrix and reinforcing fibers at 0, 2, 5, or 10 wt% were printed using digital light processing, and both were simultaneously pyrolyzed to yield the final ceramic matrix composite structure. After pyrolysis, XRD and SEAD analysis proved the existence of SiC nanocrystals and turbostratic carbon structure in the matrix, while the reinforcement phase was shown to have a turbostratic carbon structure similar to commercial carbon fibers. Thermogravimetric analysis (TGA) in air up to 1400 °C was used to evaluate the oxidation resistance of this material. TGA results showed some weight loss due to oxidation of SiC and/or carbon up to about 900 °C, followed by weight gain to about 1200 °C due to the formation of a protective SiO2 layer. Although increasing carbon fiber content negatively impacted the total mass loss for the first heating cycle, exposure of the composite to second-run air revealed negligible weight loss. This is explained by SiO2 layer formation which acts as a protective film that prevents oxygen diffusion. Oxidation of SiC and the formation of a glassy layer has been proven to protect the sample from further oxidation, as well as provide healing of surface cracks and defects as revealed by SEM analysis.

An inexpensive paracetamol sensor based on an acid-activated carbon fiber microelectrode

Paracetamol, a contaminant of emerging concern, has been detected in different bodies of water, where it can impact ecological and human health. To quantify this paracetamol, electroanalytical methods have gained support. Thus, the present study developed a simple, inexpensive, and environmentally friendly method for paracetamol quantification using a carbon fiber microelectrode based on commercial carbon fiber. To improve the carbon fiber microelectrode's paracetamol sensitivity and selectivity, it was subjected to an activation process via electrochemical oxidation in an acid medium (H2SO4 or HNO3), using 20 consecutive cycles of cyclic voltammetry. The treated (activated) carbon fiber microelectrode was characterized using scanning electron microscopy and electrochemical techniques, including chronoamperometry and electrochemical impedance spectroscopy. The H2SO4-activated carbon fiber microelectrode exhibited enhanced figures of merit, with a linear dynamic range of paracetamol detection from 0.5 to 11 μmol L−1 and a limit of detection of 0.21 μmol L−1 under optimized conditions. The method was optimized by quantifying paracetamol in commercial pharmaceutical tablets, spiked running tap water, and river water (Pita River, Quito, Ecuador, latitude −0.364955°, longitude −78.404538°); the respective recovery values were 102.89, 103.93, and 112.40%. The results demonstrated an acceptable level of accuracy and the promising applicability of this carbon fiber microelectrode as a sensor to detect paracetamol.

Effect of the Chemical Properties of Silane Coupling Agents on Interfacial Bonding Strength with Thermoplastics in the Resizing of Recycled Carbon Fibers

Upcycling recycled carbon fibers recovered from waste carbon composites can reduce the price of carbon fibers while improving disposal-related environmental problems. This study assessed and characterized recycled carbon fibers subjected to sizing treatment using N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (APS) chemically coordinated with polyamide 6 (PA6) and polypropylene (PP) resins. Sizing treatment with 1 wt.% APS for 10 s yielded O=C-O on the surface of the carbon fiber, and the -SiOH in the APS underwent a dehydration–condensation reaction that converted O=C-O (lactone groups) into bonds of C-O (hydroxyl groups) and C=O (carbonyl groups). The effects of C-O and C=O on the interfacial bonding force increased to a maximum, resulting in an oxygen-to-carbon ratio (O/C) of 0.26. The polar/surface energy ratio showed the highest value of 32.29% at 10 s, and the interfacial bonding force showed the maximum value of 32 MPa at 10 s, which is about 15% better than that of commercial carbon fiber (PA6-based condition). In 10 s resizing treatments with 0.5 wt.% 3-methacryloxypropyltrimethoxysilane (MPS), C-O, C=O, and O=C-O underwent a dehydration–condensation reaction with -SiOH, which broke the bonds between carbon and oxygen and introduced a methacrylate group (H2C=C(CH3)CO2H), resulting in a significant increase in C-O and C=O, with an O/C of 0.51. The polar/surface free energy ratio was about 38% at 10 s, with the interfacial bonding force increasing to 27% compared to commercial carbon fiber (PP-based conditions). MPS exhibited a superior interfacial shear strength improvement, two times higher than that of APS, with excellent coordination with PP resin and commercial carbon fiber, although the interfacial bonding strength of the PP resin was significantly lower.