Short Carbon Fibers Research Articles

Improved creep resistance of short carbon fiber reinforced polyetherimide composite by solution mixing method

Creep resistance is critical for ensuring the dimensional stability and safe operation of composite components. However, the creep resistance of short fiber reinforced thermoplastic composites has been rarely reported and that of the composites manufactured by conventional extrusion compounding combined with injection molding is kind of low. In this work, in order to address this issue, two short carbon fiber-reinforced polyetherimide (SCF/PEI) composites named respectively as SCF/PEIE and SCF/PEIS are prepared by both conventional extrusion compounding and our newly developed solution mixing method combined with injection molding. The solution mixing method involves the dispersion and mixing of carbon fibers within a PEI solution and allows for the retention of longer fiber lengths. Experimentally, the creep behaviors of the SCF/PEI composites were examined through tensile and flexural creep testing at various stress levels in a wide temperature range. Theoretically, the creep behaviors were characterized by employing the Schapery model and the time–temperature superposition principle (TTSP), and the impact of fiber length retention on creep resistance was quantitatively analyzed using the Fu-Lauke model. The results demonstrate that compared to the SCF/PEIE composite, the SCF/PEIS composite exhibits a higher creep fracture stress level (175 MPa) and a more extensive linear viscoelastic region (0–85 MPa) at room temperature. Furthermore, the SCF/PEIS composite was observed to have a significantly longer secondary creep stage at an elevated temperature of 210 °C. Overall, the creep resistance of the newly manufactured SCF/PEIS is significantly superior to that of the SCF/PEIE, which effectively extends the service life and operational capacity of injection-molded SCF/PEI composites.

Understanding the Carbon Additive/Sulfide Solid Electrolyte Interface in Nickel-Rich Cathode Composites and Prioritizing the Corresponding Interplay between the Electrical and Ionic Conductive Networks to Enhance All-Solid-State-Battery Rate Capability.

All-solid-state lithium batteries, including sulfide electrolytes and nickel-rich layered oxide cathode materials, promise safer electrochemical energy storage with high gravimetric and volumetric densities. However, the poor electrical conductivity of the active material results in the requirement for additional conducive additives, which tend to react negatively with the sulfide electrolyte. The fundamental scientific principle uncovered through this work is simple and suggests that the electrical network benefits associated with the introduction of short-length carbons will eventually be overpowered by the increase in bulk resistance associated with their instability in the sulfide electrolyte. However, applying just the right amount of short carbon fibres minimizes degradation of the sulfide solid electrolyte and maximizes the electron movement. Therefore, we propose the application of a low-weight-percent carbon nanotubes (CNTs) coating on the nickel-rich cathode LiNi0.8Co0.1Mn0.1O2 (NCM811) along with large-aspect-ratio carbon nanofibers (CNFs) as the primary conductive additive. When only 0.3 wt % CNTs was utilized with 4.7 wt % CNFs, an initial Coulombic efficiency of 83.55% at 0.05C and a notably excellent capacity retention of 90.1% over 50 cycles at 0.5C were achieved along with a low ionic resistance. This work helps to confirm the validity of applying short carbon pathways in sulfide-electrolyte-based cathode composites and proposes their combination with a larger primary carbon additive as a solution to the ongoing all-solid-state battery rate and instability issues.

Experimental and theoretical studies on 3D printed short and continuous carbon fiber hybrid reinforced composites

3D-printed carbon fiber composites hold significant potential in aerospace applications because of their lightweight, high strength and complex structure fabrication capabilities. However, additive manufacturing characteristics such as high porosity, anisotropy and continuous fiber content significantly affect the mechanical properties of printed parts. The aim of this study is to investigate the influence of hybrid printing of short and continuous carbon fibers on the mechanical properties and failure mechanisms of composites and to develop a model to predict elastic properties considering porosity. First, mechanical testing and characterization of short and continuous fiber reinforced polyamide (nylon) print filaments are performed. The results indicate that the elastic modulus and ultimate strength of continuous carbon fiber filaments reach 60 GPa and 1500 MPa, respectively, while the strength and elastic modulus of short carbon fiber filaments reach 60 MPa and 1 GPa, respectively. Then tensile specimens with different continuous fiber orientations and different continuous fiber placement sequences are printed and tested using a multi-material 3D printing technique. The specimens are characterized before and after testing using scanning electron microscopy and microscopy to assess the porosity and failure mechanisms of specimens with different configurations. The results show that the mechanical properties of the printed parts are much lower than those of the print filaments, which proves the serious negative impact of the material extrusion process on the mechanical properties of the printed structural parts. Finally, an analytical method for predicting the elastic behavior of printed composites is developed by introducing the porosity factor in the volume-averaged stiffness model. For continuous and short fiber filled composites with different fiber contents and printing orientations, the predicted results are in agreement with the experiments, and the prediction error is greatly reduced from 30 % to <5 %.

Silver with tribo-chemistry facilitation synergized with graphite particles for enhancing the tribo-performance of PEEK composites

The proactive design of tribo-chemistry at friction interface is an effective way to improve the quality of transfer film. Herein, silver served as an assistant in tribo-chemistry, along with graphite incorporated into the short carbon fiber (SCF)/ polytetrafluoroethylene (PTFE)/poly ether ether ketone (PEEK) composite. The lowest wear rate of 3.5 × 10-7 mm3/Nm was achieved for the composite at a graphite content of 5 wt% and a silver content of 5 wt% (Gr5Ag5) under dry friction condition, primarily benefiting from the synergistic interaction of silver and graphite. The transfer of silver and graphite to the friction interface endowed the transfer film with lubricity and load-bearing ability. Crucially, the oxides generated by silver enhanced the strength of the transfer film, and the tribo-chemical reaction involving Ag could increase the bonding of the transfer film to the metal.

Thermal and mechanical behaviour of recycled short milled carbon fibre reinforced polypropylene and recycled polypropylene composites: A comparative study

Environmental and economic factors have driven research into the recycling and applications of recycled carbon fibres (rCF). This paper presents a comparative study characterizing and comparing the mechanical and thermal performance of recycled short milled carbon fibre (rSMCF) on virgin and recycled polypropylene composites. The effects of rSMCF on VPP and RPP on mechanical performance were analysed and compared. At 5 wt% rSMCF, recycled polypropylene achieved 52.3% and 47.3% improvement on tensile and flexural modulus, while at the same rSMCF loading, virgin polypropylene only improved 37.7% and 17.5%, respectively. The un-notched impact strength of RPP-based composites reduced from 83.2 kJ/m2 to 60.1 kJ/m2 when rSMCF content increased from 1 wt% to 5 wt%, indicating future work should enhance the fibre/polymer interface performance. Crystal contents (χ0) of the PP/rSMCF composites were investigated by differential scanning calorimetry (DSC), and the results were analysed and mapped to the mechanical performance. The results of this study propose a novel scalable method for the production of high-performance VPP/RPP composite materials using rSMCF.

Tailoring the additional content of short carbon fiber in the reduced graphene oxide-Cu self-lubricating composites for enhanced mechanical and tribological performance

The reduced graphene oxide-Cu self-lubricating composites with short carbon fiber fillers were fabricated by powders wet-mixing combined with hot-pressed sintering process. The impacts of short carbon fiber content on microstructure, mechanical and tribological performance of reduced graphene oxide-Cu composites were characterized. The reduced graphene oxide/carbon fiber hybrid fillers were randomly distributed in the sintered bulk compacts. The hybrid filled composites achieved enhancement in mechanical and tribological properties. With increasing carbon fiber content, hardness and compressive yield strength of the prepared composites were increased, and both friction coefficient and wear rate showed a constant decrease trend under different loads. Owing to the synergy effect of reduced graphene oxide/carbon fiber hybrid lubricant fillers during sliding together with the greatly enhanced hardness and yield strength, up to 0.6 wt% carbon fiber incorporation resulted a lowest friction coefficient and decreased wear rate. Randomly distributed reduced graphene oxide/carbon fiber hybrid fillers provided the lubrication to reduce friction and wear for Cu matrix.

Effect of Filler Content and Treatment on Mechanical Properties of Polyamide Composites Reinforced with Short Carbon Fibres Grafted with Nano-SiO₂

Effect of Filler Content and Treatment on Mechanical Properties of Polyamide Composites Reinforced with Short Carbon Fibres Grafted with Nano-SiO₂

Enhancing interlaminar fracture toughness and shear strength of carbon fiber composite laminates via orientation of nickel-plated short carbon fibers in a magnetic field

This study aimed to enhance the interlaminar mechanical properties of carbon fiber composites by incorporating nickel-plated short carbon fibers (Ni@SCFs) between adjacent layers in a magnetic field. Herein, non-flocked composites, flocked composites with unoriented Ni@SCFs, and flocked composites with oriented Ni@SCFs using a magnetic field were fabricated to investigate the impact of fiber orientation on the mode I interlaminar fracture toughness (GIC) and interlaminar shear strength (ILSS) of the composite laminates. It was observed that Ni@SCFs were distributed at varying vertical angles between adjacent layers under the influence of the magnetic field. The areal density of oriented Ni@SCFs was systematically increased, resulting in notable enhancements in both initiation and propagation of GIC for flocked composites. At a flocking density of 6 g/m2, maximum values reached 533 J/m2 and 769 J/m2 respectively, representing a substantial increase of 52 % and 63 % compared to non-flocked composites. Additionally, the ILSS of flocked composites with oriented Ni@SCFs significantly improved to 55.83 MPa at a flocking density of 2 g/m2, indicating an increase of 27 % over non-flocked composites. The oriented Ni@SCFs played a crucial role in inhibiting crack propagation through the fiber bridging effect.

Wear and Friction Behavior on Extrusion-Based 3D Printed Short Carbon Fiber Reinforced PETG Composites with Annealing and Laser Treated Effects

Wear and Friction Behavior on Extrusion-Based 3D Printed Short Carbon Fiber Reinforced PETG Composites with Annealing and Laser Treated Effects

Dependence of the mechanical properties of nylon-carbon fiber composite on the FDM printing parameters

Nylon-based polymer reinforced with short carbon fibers (PA-CFs), fabricated using the Fused Deposition Modeling (FDM) 3D printing process, has been proposed for various applications. However, the mechanical performance of these materials as a function of printing parameters, including wall thickness at infill contents < 100 %, has yet to be reported in the literature. This paper focuses on the effects of infill percentage, nozzle temperature, and wall thickness on the porosity content, microstructure, and mechanical properties of PA-CF specimens. Employing a Taguchi (L9 − 3^3) design of experiments, tensile and flexural testing were conducted to assess their mechanical response. The printing temperature induces microstructural changes, promoting interlayer debonding due to voids and pores at wall- and skin-core interfaces. Wall thickness significantly impacts tensile strength and can be maintained between 0.8 and 1.35 mm for maximum flexural strength, while maximal tensile strength can only be achieved with a wall thickness between 1.15 and 1.5 mm.

Evaluation of fatigue characteristics of 3D printed/composites reinforced with carbon fiber using design of experiments

AbstractThis study investigates the fatigue characteristics of 3D‐printed composites made from polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS), reinforced with carbon fiber. It involves designing and building a rotating bending fatigue machine, creating standard specimens via FDM, and applying DOE using Taguchi method. Standard specimens are subjected to cyclic loading with a print orientation of 0°, 45°/−45°, and 90°, motor speed and load. Materials such as PLA, ABS, PLA‐CF, and ABS‐CF are tested by maintaining a consistent layer thickness of 0.16 mm and 99.99% infill density while varying stress levels. PLA‐CF outperforms PLA, ABS, and ABS‐CF in fatigue life, with 0° print orientation exhibiting superior fatigue strength. Statistical analysis underscores the significance of print direction, material composition, and stress level. Additionally, the study aims to construct S‐N curves for 3D‐printed PLA/ABS composites with carbon fiber reinforcement, advancing our understanding of mechanical properties and print parameter optimization for enhanced fatigue performance in 3D‐printed composites.Highlights Fatigue characteristics of 3D printed composites made from PLA and ABS, reinforced with carbon fiber investigated. Four polymer composites were used: PLA, ABS, PLA‐CF (short carbon fiber), and ABS‐CF (short carbon fiber). The research focused on the impact of 3D print orientation on fatigue properties, considering print angles of 0°, 45°/−45°, and 90°, alongside adjustable factor like motor speed and load. With a consistent layer thickness of 0.16 mm and 99.99% infill density, the fatigue tests were conducted under stress‐controlled conditions at varying stress levels. Results demonstrate that PLA‐CF specimens exhibit superior fatigue lifetimes compared to PLA, ABS, and ABS‐CF samples.

Experimental and numerical investigation of crash performances of additively manufactured novel multi-cell crash box made with CF15PET, PLA, and ABS

Abstract In this study, a novel multi-cell crash box was designed and produced using 15 % short carbon fiber reinforced polyethylene terephthalate (CF15PET), polylactic acid (PLA), and acrylonitrile butadiene styrene (ABS) filaments using one of the additive manufacturing methods, the melt deposition method (FDM). All structures’ maximum force and energy absorption performances have been investigated. As a result of the test, it was determined that the crash box, which best meets the high energy absorption and folding properties, one of the expected features in crash boxes, has parts manufactured using ABS and CF15PET materials. According to the test result, it was found that the energy absorption of the ABS crash box is 11 % higher than CF15PET and approximately 4.5 % higher than PLA. It has been determined that the maximum force response value of the ABS box is 5 % higher than CF15PET and 12 % higher than PLA. As a result, it has been determined that ABS and CF15PET materials can be used in crash boxes and can form an idea about the design and test result by designing and analyzing crash boxes using finite element programs.

Wear-resistant phenolic composites reinforced with attapulgite and short carbon fibers for applications subjected to both dry and oil-lubricated sliding

Attapulgite (AT) nanofibers were integrated into phenol-formaldehyde resin (PF) and PF composites reinforced with short carbon fibers (CF). Inclusion of AT significantly enhances the wear resistance of PF under both dry and oil-lubrication conditions. The hybrid nanocomposites, reinforced with both AT and CF, exhibit a high mechanical strength. Interestingly, AT and CF lower synergistically the friction coefficient of PF subjected to harsh dry sliding conditions. The hybrid nanocomposites exhibit excellent tribological performance under both dry and oil-lubrication conditions. Tribofilms’ nanostructures were comprehensively analyzed for disclosing dominant tribological mechanisms. Outcome of this work provides new ideas for developing tribo-materials of a high adaptability to various dry/oil-lubrication conditions.

High-temperature aging and long-term mechanical properties of polyphenylene sulfide composites for marine use

ABSTRACT Advanced polymeric composites and manufacturing techniques promote developments of marine structures significantly (e.g., spare parts supply chain of shipbuilding and maintenance). In this paper, the GNP/CF-PPS (graphene nanoplatelets short carbon fibre polyphenylene sulfide composite) samples are prepared by mechanically mixing CF-PPS plastic pellets and GNP particles. The mixed compound is 3D-printed by material extrusion additive manufacturing, and the bending mechanics test is carried out to explore how nanoreinforcement affects the ability of printed composites to perform under high temperature conditions. The results show that CF-PPS and GNP/CF-PPS samples have the highest flexural strength at room temperature. As the temperature rises to 260°C, the stiffness increases by 4.8% and 6.7% respectively, while the deflection decreases by 30.4% and 25.6% respectively. The characterisation results of scanning electron microscopy (SEM) show that the cross-sectional pores of CF-PPS samples after adding GNP are relatively reduced, indicating the improvement in the structural stability.

High performance Csf/SiC ceramic matrix composites fabricated by material extrusion 3D printing and precursor infiltration and pyrolysis

Material extrusion (ME) 3D printing is an emerging technology to fabricate short carbon fiber reinforced SiC ceramic matrix composites (Csf/SiC CMCs) with highly oriented short carbon fibers. In this study, the Csf/SiC CMCs were fabricated by ME 3D printing combined with the following precursor infiltration and pyrolysis (PIP). The short carbon fibers could be well kept after the PIP process. The effects of solid loading and fiber content on the microstructure and mechanical properties of the Csf/SiC CMCs were also investigated. Higher solid loading was beneficial for obtaining the denser Csf/SiC CMCs with more oriented fibers. The introduction of short carbon fibers brought more pores. The bending strength and fracture toughness of Csf/SiC CMCs first increased and then decreased with the increase in fiber content. The pulling-out and breakage of short carbon fibers contributed to the improvement of mechanical properties. High performance Csf/SiC CMCs with a bending strength of 212.74 MPa and fracture toughness of 5.84 MPa m1/2 were simultaneously achieved when the solid content was 50 vol% and the fiber content was 20 vol%. It is believed that this study can provide some understanding of the 3D printing of fiber reinforced CMCs.

Improving flexural performances of fused filament fabricated short carbon fiber reinforced polyamide composites with natural‐inspired structural design

AbstractBoth the nacre‐like bionic microstructure and the spiral laminated bionic configuration exhibit superior damage‐tolerance characteristics. On the basis of this observation, the design concept of the bionic helical‐interlayer configuration is innovatively integrated into the design of a bionic nacre‐like honeycomb structure. By systematically studying different spiral angles of honeycomb's interlayer stacking forms, their influence on the structural performance is deeply discussed with four‐point bending tests. Mechanical samples are carefully prepared using short carbon fiber reinforced polyamide composites (i.e., PA6‐CF) through conventional fused filament fabrication (FFF) 3D printing technology, where the accuracy and reliability of the designed bio‐inspired samples are ensured. The experimental results reveal significant improvements in bending strength and elastic modulus across various bionic nacre‐like honeycomb spiral structures compared to uniformly overlap configurations. In particular, the SH‐7.5 sample shows a remarkable 35.47% increase in bending strength and a 65.10% increase in elastic modulus over the SH‐11.25 sample. SEM‐based microstructural analyses are carried out to further explore the fracture mode of the carbon fibers, implied the helical configuration adopted in the nacre‐like honeycomb structure enhances the flexural resistant ability of the PA6‐CF composites. The findings above bear important guiding significance and reference value for the design of lightweight and high damage‐tolerance composite structures.Highlights A novel bio‐inspired structure is implemented to improve the mechanical performance of fused filament fabricated polyamide composites, where the bionic spiral helical configuration is integrated into high‐fracture‐resistance nacre‐like honeycomb structures. Mechanical testing results indicate that a helix angle under 10° results in a significant improvement in the structural performance of flexural strength. Microstructural analysis reveals that the helical configuration enhances the load‐bearing functionality of reinforcing carbon fibers in the printed polyamide composites. FFF 3D printing enables further implementation of the proposed bio‐inspired novel structure for lightweight and damage‐tolerant composite applications with high customization demands.

Using pyrolytic carbon-coated short carbon fiber to fabricate Csf/ZrB2–SiC composites by direct ink writing and precursor infiltration pyrolysis

Direct ink writing (DIW) offers significant advantages for efficient manufacturing of complex ceramic composite components. However, the mechanical properties of short carbon fiber-reinforced ceramic composites fabricated by DIW technology were not ideal, mainly be ascribed to the absence of a suitable coating on the fiber as an interface. In this work, Csf/ZrB2 green bodies were printed by an optimized extrusion process using pyrolytic carbon-coated short carbon fibers (Csf). High-performance Csf/ZrB2–SiC composites were obtained through the infiltration and pyrolysis of SiC precursor six times. With increasing Csf content, the dimensional deviations decreased and the mechanical properties increased. When the Csf content was 30 vol%, the dimensional deviation of the Csf/ZrB2–SiC composite was less than −0.5 % in the X and Y directions and about −2 % in the Z direction. A marked increase in the flexural strength and fracture toughness of the composite was also obtained, reaching 275.0 MPa and 5.26 MPa m1/2, respectively.

The Role of Triboloading Conditions in Tribolayer Formation and Wear Resistance of PES-Based Composites Reinforced with Carbon Fibers.

In this paper, the tribological characteristics of polyethersulfone-based composites reinforced with short carbon fibers (SCFs) at aspect ratios of 14-250 and contents of 10-30 wt.% are reported for linear metal-polymer and ceramic-polymer tribological contacts. The results showed that the wear resistance could be greatly improved through tribological layer formation. Loading PES with 30 wt.% SCFs (2 mm) provided a minimum WR value of 0.77 × 10-6 mm3/N m. The tribological layer thicknesses were estimated to be equal to 2-7 µm. Several conditions were proposed, which contributed to the formation of a tribological layer from debris, including the three-stage pattern of the changing kinetics of the time dependence of the friction coefficient. The kinetics had to sharply increase up to ~0.4-0.5 in the first (running-in) stage and gradually decrease down to ~0.1-0.2 in the second stage. Then, if these levels did not change, it could be argued that any tribological layer had formed, become fixed and fulfilled its functional role. The PES-based composites loaded with SCFs 2 mm long were characterized by possessing the minimum CoF levels, for which their three-stage changing pattern corresponded to one of the conditions for tribological layer formation. This work provides valuable insight for studying the process parameters of tribological layer formation for SCF-reinforced thermoplastic PES composites and revealing their impact on tribological properties.

Enhanced thermal management strategy for supercapacitors using phase change materials: A numerical investigation

The integration of phase change materials (PCMs) presents a promising possibility for enhancing the thermal management of supercapacitors (SCs), which are vital components in various energy storage systems. This research focuses on investigating the thermal behavior of SCs with integrated PCM, employing finite element method (FEM) simulations to solve the transient thermal problem. Through a comparative analysis at various time instants, the transient thermal response of SCs is examined, shedding light on the efficacy of PCM-based thermal management strategies. Moreover, parametric studies are conducted to investigate the influence of PCM key characteristics, like melting temperature and layer thickness on the SC thermal response. Additionally, the impact of enhanced PCM thermal conductivity is explored by integrating high-conductive short carbon fibers (CF) within the PCM matrix. This investigation encompasses various PCM melting points, allowing for a comprehensive understanding of the interplay between PCM properties and SC thermal response. The results indicate that a notable decline in the highest temperatures of the SC can be achieved, leading to a reduction of about 9 °C depending on the PCM melting temperature and the improved thermal conductivity. The obtained results emphasize the effectiveness and practical feasibility of the proposed thermal management strategy. The modeling approach presented provides a robust tool with significant efficiency in reducing computational time for analyzing the thermal behavior of large models, as the utilization of the homogenization technique notably decreases the computational time. The findings of this study not only provide insights into optimizing PCM-based thermal management strategies for SCs but also contribute to advancing the design and performance of energy storage systems by addressing crucial thermal challenges.

High strength microcellular thermoplastic polyimide/carbon fiber composite foams containing flexible ether amine, rigid diaminodiphenyl ether, and triaminopyrimidine moieties: Synthesis and fabrication

In this study, pyromellitic dianhydride (PMDA) and polyetheramine D230 were used as the primary polymerization monomers, with 2,4,6-triamino pyrimidine (TAP) as a chain extender. By introducing aromatic ring-containing 4,4′-diaminodiphenyl ether (ODA) and precisely controlling its molar ratio with D230, a highly branched, high-temperature-resistant thermoplastic polyimide (TPI), was successfully developed. The optimal thermal imidization temperature was determined to be 250 °C. Incorporating surface-modified short carbon fibers (SCF) via melt blending significantly improved the mechanical properties, with tensile and impact strengths increasing fourfold and sevenfold, respectively, at 10 phr of SCF. TPI foam prepared using supercritical carbon dioxide (scCO2) foaming technology exhibited excellent performance, achieving a regular hexagonal structure, cell sizes of 10.19 μm, and a cell density of 1.68 × 1010 cells/cm3 at an ODA to D230 molar ratio of 1:9. The TPI/SCF composite foam, with 3 phr SCF under 20 MPa saturation pressure and 120 °C foaming temperature, achieved a 90 % closed-cell ratio and a 300 % increase in compression strength at the same foam density. Compared to traditional thermoset PI foams, TPI/SCF foam offers smaller cell sizes and higher compression strength, demonstrating significant commercial potential. Backward differentiation shows that TPIF compression is constant at 0.035 ± 0.005 in the [0,0,1] lattice direction. This research provides theoretical and practical insights for preparing high-performance TPI foam for high-temperature applications.