Mechanical Properties Of Carbon Fibers Research Articles

Influence of carbon fiber failure mode caused by TiO2 coating on the high temperature tensile strength of carbon fiber reinforced 7075 Al alloy composites

To enhance the mechanical properties of carbon fiber (CF) reinforced 7075 Al alloy material at high temperature conditions, TiO2 coating was prepared on the surface of CF by chemical vapor deposition. The composites were prepared by hot pressing sintering and hot extrusion methods. The evolution of the compositional components of the composite interface was investigated. The density, hardness, and tensile strength of the samples were measured, and the strength/density ratio of the samples was calculated at 150 °C. The results indicate that the tensile strength of coated CF reinforced composite (535 MPa) was increased by 21.3% and 5.7% compared to the tensile strength of 7075 Al alloy (441 MPa) and uncoated CF reinforced composite (506 MPa), respectively. Furthermore, the strength/density ratio of the composite also increased with the addition of TiO2 coating. The enhancement of coating on CF on tensile strength is attributed to the transformation of CF failure mode.

Effect of silver plating and sintering temperature on the microstructure and mechanical properties of carbon fiber reinforced Cu matrix composites

Recycled carbon fibers are primarily utilized as reinforcement in the production of composite materials, and they have steadily become a hot topic in the twenty-first century. However, the presence of large amount of residual resin, crack damage and graphitized surface layer on the surface of recycled carbon fibers leads to the reduction of their mechanical properties. In this study, Cu matrix composites reinforced with carbon fiber were created using the spark plasma sintering process at 700–850 °C sintering temperature. The surface coating treatment was done to recycled carbon fiber in order to enhance the interfacial bonding between the carbon fiber and Cu matrix, and the ideal surface Ag plating parameters were investigated and established. Results have shown that the Ag coating on the fiber surface diffuses at different sintering temperatures, forming a Ag–Cu solid solution, which has a solid solution-strengthening effect on the substrate. When the sintering temperature is below 800 °C, some Ag atoms will precipitate out of the matrix, forming a small amount of Ag precipitation phase. As the sintering temperature increases, the tensile strength of the composite increases and then decreases, the compressive strength gradually decreases and the flexural strength gradually increases.

Geometric phase analysis for characterization of 3D morphology of carbon fiber reinforced composites

In carbon fiber-reinforced resin matrix composites, differences in the mechanical properties of carbon fibers and matrix resins can lead to differences in height, causing step faults at the interphase during grinding and polishing. Accurately and efficiently characterizing the step height at the interphase is crucial for analyzing the mechanical properties and residual stress distribution of the composite materials. In this paper, an orthogonal grating, with a frequency of 10,000 lines/mm, was prepared on the surface of the composite material using the SEM electron beam grating technique. The surface morphology of the T700 carbon fiber-reinforced epoxy resin matrix composite was analyzed using the geometric phase analysis method. The average step height between the fiber and matrix was found to be 128.6 nm. Moreover, the geometric phase analysis method can provide a morphology distribution map within the range of 155 × 100 μm2. This research will provide an effective way to quantitative characterization of three-dimensional surface morphology of composite materials.

Construction of Polar Functional Groups on the Surface of a High-Modulus Carbon Fiber and Its Effect on the Interfacial Properties of Composites.

The interfacial bonding between carbon fibers and the resin matrix affects the mechanical properties of carbon fibers, and the increase of modulus brings a challenge to the interfacial properties of carbon fibers. The traditional anodic oxidation with ammonium bicarbonate as an electrolyte has a limited effect on the surface treatment for high-modulus carbon fibers. In this paper, anodic oxidation with an acidic electrolyte is used to treat high-modulus carbon fibers. The influence mechanism of a graphitized structure on the anodizing reaction of the carbon fiber surface was studied. Raman spectroscopy, XPS, scanning electron microscopy, dynamic contact angle, and micro-debonding were used to characterize the effect of surface treatment and its influence on interfacial properties. The results show that with a certain concentration of sulfuric acid as an electrolyte, the oxidation of the carbon fiber surface with high modulus occurs more on the graphite boundary defects. Carbonylation occurs mainly in carbon fibers with high modulus. The surface of the carbon fiber with a relatively low modulus is mainly hydroxylated and carboxylated. The surface energy and interfacial properties of high-modulus carbon fibers were improved effectively by anodic oxidation with sulfuric acid as an electrolyte. Under the condition that the mechanical properties of carbon fibers are not decreased, the surface energy of high-modulus carbon fibers with 352 GPa increases from 36.17 to 45.41 mN/m, and the interfacial shear strength (IFSS) with the epoxy resin increases by 80.8% from 34.9 to 63.1 MPa. When the fiber modulus is 455 GPa, the surface energy of the carbon fiber increases from 32.32 to 43.73 mN/m, and IFSS increases by 253.4% from 11.8 to 41.7 MPa.

Determination of the shaping behavior of thermoplastic composite materials required for simulation of thermoforming

The shaping of composite consolidated plates into products is a complex process. To obtain a defect-free product, we have to bear in mind that thermoplastics reinforced with a fabric practically do not stretch, and their shaping behavior is determined by the mechanisms of shear deformations within a layer or between layers, by the processes of sliding a composite over the surface of tooling and by the flexural rigidity of the consolidated plates. Due to the complex behavior of the material during deformation, the optimization of the thermoforming process by trial and error is rather expensive in implementation and can be successfully replaced by a preliminary simulation. The available software packages intended for modeling the thermoforming process which provide construction of a correct model of the material consistent with the reality, require the introduction of input parameters for the drape of the consolidated plate, its flexural stiffness, the coefficient of friction between layers and with tooling. However, until now there are no standards for their measurement, which significantly hinders the process of modeling the thermoforming of products from consolidated plates based on thermoplastic binders. We present experimental data on the determination of some physical and mechanical properties of carbon fiber reinforced plastics based on polypropylene PP01030, including tensile-displacement tests of the sample, tests with a moving frame that provide evaluating the shear behavior of thermoplastic composite materials, as well as tests for determining the interlayer friction and friction of a composite with tooling. The tests were carried out at the melting temperature of the matrix using specialized tooling, made taking into account the experience of foreign research groups in physical and mechanical testing of thermoplastic composite materials. A method for determining the flexural rigidity of thermoplastic carbon fiber reinforced plastics is proposed. The presented tooling does not require the application of a complex force, and needs only standard tensile test clamps of the testing machine. The data obtained from the physicomechanical tests can be used in virtual modeling of the thermoforming process of consolidated composite plates.

Advances in Insight of Radial Heterogeneous Microstructure and Its Relevance to Mechanical Properties of Polyacrylonitrile‐Based Carbon Fibers

Polyacrylonitrile‐based carbon fibers (CFs) have demonstrated unparalleled physical and mechanical properties and are considered a promising material for aerospace, transportation, medical devices, and other applications. However, the current understanding of the heterogeneous structure of carbon fiber is still vague, and the relationship between the heterogeneous structure and the mechanical properties of carbon fiber is also unclear. In this review, the literature on the radial heterogeneous structure of CFs is summarized from four points of view: morphological structure, physical properties and chemical structures, mechanical properties, and structural models by combining different characterization tools such as nanoindentation, nanoscale infrared spectroscopy, and synchrotron wide‐angle X‐ray diffraction. First, the size and orientation of graphite microcrystalline, the degree of graphitization, density distribution, modulus distribution, chemical functional group distribution, and other physical and chemical properties of carbon fiber cross‐sectional structures are discussed. Afterward, the relationship between the mechanical properties of carbon fiber and the heterogeneous structure is analyzed. Finally, the currently accepted models of the heterogeneous structure of carbon fibers are summarized and made some suggestions for research on the heterogeneous structure of carbon fibers.

Mechanism of the impact of the sizing agent chain length on the interfacial mechanical properties of carbon/epoxy composites

The mechanical properties of carbon fiber reinforced composites can generally be improved by interfacial design, and one of the possible strategies involves the manipulation of the sizing agent polymer. Although this approach can be industrialized with relative ease compared to grafting functional groups and chemical deposition nano-fillers on the surface of fibers, elucidating its regulatory mechanisms remains a challenge. Herein, molecular simulations are utilized to study the interfacial modification of typical carbon fiber/epoxy composites with different sizing chain length structures, and the physical and chemical characteristics of the interface are firstly quantified. An inhomogeneous distribution of the interfacial phase is further divided into three layers, and each layer is correlated with the evolution of the mechanical properties of the composite. The first layer in the interfacial phase is closest to the fiber surface, which is highly restrained by physical diffusion and exhibits poor mechanical properties. However, the first layer can be considered as an equivalent to a “softener”, which is beneficial for conferring better pull-out and bending strength. The second layer has the strongest interaction between the sizing agent and matrix, is controlled by a combination of physical diffusion and chemical interaction, which are particularly significant for interfacial transfer. The interfacial properties of the third layer are controlled by chemical reactions, which are closer to that of the resin matrix. The present study emphasizes the importance of gradient design of mechanical properties between the first and second layers in the hierarchical interface, paving the foundation and direction for a systematic framework of gradient design, optimization, and matching of interfaces in carbon fiber composites.

A new strategy for improvement of interface and mechanical properties of carbon fiber/epoxy composites by grafting graphene oxide onto carbon fiber with hyperbranched polymers via thiol‐ene click chemistry

AbstractFor the purpose of improving the interface and mechanical properties of carbon fiber reinforced polymer (CFRP) composites, a new strategy was proposed to graft the graphene oxide (GO) onto carbon fiber (CF) surface fast and effectively via thiol‐ene click chemistry reaction using vinyl‐terminated hyperbranched polyester (VHBP) as bridging agent. The successful synthesis of the CF‐VHBP‐GO hybrid reinforcement was verified through Fourier transform infrared spectroscopy (FT‐IR), x‐ray photoelectron spectroscope, thermogravimetric analysis, and scanning electron microscopy. The simultaneous introduction of GO and hyperbranched polymers changed the fiber surface morphology and improved the wettability and surface energy of CF. Judging from the results of the micro‐droplet test, the interfacial shear strength for epoxy (EP) based composite reinforced with CF‐VHBP‐GO was significantly increased by 137.8% compared to untreated CF/EP composite owing to the synergistic effect of VHBP and GO. In addition, the tensile and flexural strength for CF‐VHBP‐GO/EP composite were improved by 47.6% and 65.8%, respectively, compared to untreated CF/EP composite, respectively. This work offers a promising technique for developing high‐performance CF composites with excellent interface properties.

Cyclic aging analysis of CFRP and GFRP composite laminates

When a composite laminate is subjected to humidity, moisture diffusion occurs depending on the number and thickness of the lamina. Water diffusion changes the mechanical response of laminates and usually causes a significant reduction of the mechanical properties of the composite specimens in ocean structures. One of the most important mechanical properties of laminates is flexural stiffness which should be considered in the design procedure. Despite the extensive research on single cycle aging of composites, cyclic aging of these materials is less explored. The aim of the current research is to investigate the variation of mechanical properties of carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP) composites as a substrate in adhesive joints with the same initial flexural stiffness values subjected to cyclic wet/dry aging conditions for long-term structural applications. The matrix used in the CFRP and GFRP composites are based on epoxy and vinyl ester, respectively. Both unaged and cyclically aged samples were characterized by tensile and three-point bending tests. In order to simulate the moisture absorption condition of composites in adhesive joints, one side of the composite laminates was sealed with aluminum foils and three sides were exposed to humidity. The interaction between the composite thickness and the number of aging cycles was also investigated. The experimental results show that in cyclic aging condition, the reduction of flexural stiffness in CFRP is more than GFRP laminates and GFRP laminates is more suitable for ocean applications.

Influence of void defects on impact properties of CFRP laminates based on multi-scale simulation method

The void defects produced in the composite material manufacturing process directly affect the basic mechanical properties of Carbon fiber reinforced polymers (CFRP), resulting in weakened impact resistance. This paper combines the advantages of the fast calculation speed of the macro-model and the more accurate micro-model, and proposes a multi-scale method that can judge fiber and matrix damage at the micro-scale. According to this multi-scale method, the representative volume element (RVE) of the unidirectional (UD) carbon fiber was studied, and the relationship between the six elastic properties of the CFRP and the void defects and fiber volume fraction was obtained. It was assumed that the void defects were of the same size and randomly distributed in the matrix, ignoring the effect of void shape. Analyze the impact resistance of CFRP laminates containing void defects, and the relationship between each characteristic parameter and the content of void defects. Exploring the impact resistance of CFRP laminates containing void defects, it is found that under rebound conditions, as the void content increases, the peak force decreases, the maximum displacement and the final energy absorption increase, but they are not linear. Under penetration conditions, the peak force and final energy absorption decrease nonlinearly with the increase void defect content. The innovation of this paper is to combine the multi-scale analysis method and the void defects, and obtain the relationship between the void content and the elastic properties of the CFRP, and apply the CFRP laminate containing the void defects to the impact condition, to explore its impact on impact performance.

Experimental investigation on workability and mechanical properties of carbon fiber reinforced high-strength concrete (HSC) containing waste bakelite aggregate (WBA)

High-strength concrete (HSC) is a type of concrete that is, due to its improved mechanical and durability properties, most often used in the construction of high-demand structures such as bridges, structural elements in aggressive environments, skyscrapers, and large-span constructions. In order to obtain high-strength concrete, a larger amount of cement is required, which can lead to questionable ecological acceptability of this material. To reduce the ecological footprint of this material, supplementary cementitious materials such as silica fume or metakaolin are often used. By reducing the porosity and increasing the density of the concrete mixture, fine particles of supplementary cementitious materials have a positive effect on the mechanical and durability properties of high-strength concrete. Along with cement and supplementary cementitious materials, another important component of high-strength concrete is aggregate, which is in most cases a fine aggregate. In this research, the natural fine aggregate was partially replaced with bakelite plastic waste, and the influence of this replacement on the fresh and hardened properties of high-strength concrete was presented. Seven mixtures were designed, a reference mixture and six other mixtures in which supplementary cementitious materials, waste bakelite aggregate, and carbon fibers were combined to produce environmentally friendly high-strength concrete. 5 % of the cement mass was replaced with silica fume or metakaolin, 10 % volume of natural fine aggregate was replaced with waste bakelite aggregate (WBA) and carbon fibers were added in the amount of 0.5 % of the cement mass. In a fresh state, the workability of HSC is determined by using a flow table. To determine the influence of waste bakelite aggregate on mechanical properties, flexural and compressive strength tests were carried out on 7- and 28-day-old samples. The test results indicate that the combined effect of waste bakelite aggregate, supplementary cementitious materials, and carbon fibers can be a promising solution not only to improve high-strength concrete mechanical properties but to potentially save millions of tons of natural fine aggregate and preserve natural resources and the environment.

The Investigation of General Properties of Carbon Fiber (CF) Composites - Preliminary Study

The most commonly used materials in the production of high-performance CFs are cellulose, polyacrylonitrile, and pitch. Polyacrylonitrile (PAN)-based fibers dominate the market (representing nearly 90% of total CF production), with some companies producing more than 10,000 tons per year. However, the current technique's high cost (the combined cost of the precursors and stabilization accounts for 70% of total CF synthesis cost) limits the technology's applicability. Carbon fiber manufacturing is characterized by a high energy demand due to long processing times and energy intensive thermal processes. PAN-based CFs are difficult to commercialize due to the time-consuming pre-oxidation step, which significantly raises the manufacturing cost. As a result, advanced processing technologies aimed at reducing CF production costs should be developed. They were consisting of a thin but strong crystalline filament of carbon. This experimental study was to learn the mechanical properties of carbon fiber using Universal Testing Machine (UTM). There was a section where we made a phone case out of Polyacrylonitrile (PAN) carbon fiber and compared it to other materials for phone cases. The phone cases of carbon fiber composites as the one examples of consumer product was made from the woven carbon fiber then was hardened by hard epoxy mixed with resin epoxy. Then, the phone cases were tested with UTM machine to compare the tensile strength and high modulus. Other than that, there were few samples with different composition of PAN powder mixed with different composition of sodium thiocyanate. The results of the testing shows that the carbon fiber had the high tensile strength than the other materials of phone cases which were silicone and thermoplastic polyurethanes (TPU). The microstructure of carbon fiber has a significant impact on its mechanical properties.

Improving interfacial adhesion and mechanical properties of carbon fiber reinforced polyamide 6 composites with environment-friendly water-based sizing agent

In this study, a water-based aminoethylpiperazine-polyamide (AEPPA) is synthesized and its water-based sizing agent is prepared to improve the interfacial properties of carbon fiber reinforced polyamide 6 (CF/PA6) composites. The results show that the AEPPA sizing layer enhances the wettability of CF surface, thereby promoting the sufficient impregnation of PA6 resin on the fiber surface. Meanwhile, a strong interface is formed due to the interdiffusion and hydrogen bond formation between AEPPA and PA6 molecular chains. Accordingly, the interfacial shear strength increases by 29.3% and 20.2% from 41.9 MPa for as-received and 45.1 MPa for desized CF/PA6 composites to 54.2 MPa for 4 wt% AEPPA sizing agent treated CF/PA6 composites. In addition, to clarify the applicability of the resultant sizing agent, unidirectional CF/PA6 prepregs are prepared, and the mechanical properties of CF/PA6 composites are evaluated in detail. The average interlaminar shear strength, tensile strength and flexural strength increase by 14.2%, 10.5% and 20.0% from 73.8, 2198.1 and 1393.6 MPa for desized CF/PA6 composites to 84.3, 2638.7 and 1539.9 MPa for those treated with AEPPA sizing agent due to the effective stress transfer across the interface, respectively. Moreover, the cross-section morphologies and fracture behavior are analyzed to verify the improvement of mechanical properties. Furthermore, the strengthening mechanism of interfacial properties is intensively discussed.

Mechanical properties of carbon fiber/PPS laminates processed by hot compression molding under different consolidation cycles

AbstractHigh‐performance thermoplastic composites based on semipregs of poly(phenylene sulfide) (PPS) reinforced with carbon fiber (CF) have been widely used in the aerospace industry due to their excellent mechanical properties and thermal stability. In this work, CF/PPS laminates were processed by hot compression molding. The processing parameters (pressure and temperature of processing) were investigated as well as the effect of the number of semipreg layers. The neat PPS matrix and CF/PPS semipreg were evaluated by rheological and thermal properties, respectively, to verify the best processing temperature for the CF/PPS composite laminates. The CF/PPS laminates obtained were inspected by ultrasound and differential scanning calorimetry analyses, and then the standardized specimens were prepared. The mechanical properties were evaluated by tensile test and interlaminar shear strength (ILSS) tests. Morphological characteristics of fracture surfaces also were analyzed by scanning electron microscopy. The ultrasound inspections showed differences among the processed laminates with the presence of defects mainly around the edges of samples. Based on ultrasound maps, the worst regions of laminates were discharged and not used to cut the specimens utilized in the mechanical characterization. Thermal, mechanical, and morphological analyses of the six laminates processed with different consolidation cycles did not show significant differences, showing good CF‐PPS matrix interface and similar results of crystallization (~23%), tensile strength (776–858 MPa), and ILSS (59–68 MPa).

Effect of NH2-MWCNTs sprayed carbon fiber on the mechanical properties of carbon fiber reinforced polycarbonate composite for lightweight structural applications

In this work, amine-Multi-walled Carbon Nanotubes (MWCNTs) were reinforced on the surface of fiber fabric by solvent spray deposition method in order to improve the mechanical and thermal properties of carbon fiber/polycarbonate film (CF/PC) stacked composites. The hot press method was used to fabricate the CF/PC composites with varied NH2-MWCNTs concentrations of 0.1, 0.3, 0.5, and 0.7 wt.%, as well as the reference composite. The multifarious assembly features of Carbon nanotubes (CNTs) on the fiber surface exhibit greater interfacial mechanics and have a major influence on the load transfer efficiency of the composite. In comparison with reference CF/PC composite, the tensile strength (384.55 MPa) and modulus (23.78 GPa) of composites increase by 67% and 40% respectively for 0.1% NH2-MWCNT reinforcement, whereas flexural strength and flexural modulus increase by 98% and 80%. However, as compared to the 0.1% CNT reinforcement, the impact strength of the 0.7% increases over 6% by absorbing substantial fracture energy. The inclusion of MWCNTs lowers the glass transition temperature (Tg) of composites due to the role of molecular conformations in free surface volume of the polymer. X-ray Photoelectron spectroscopy (XPS) and FTIR analysis confirms the functional groups present in the nanocomposite. Field Emission Scanning electron microscopy (FESEM) was used to analyze the dispersion and adhesion surface morphology of MWCNTs on fiber and the fiber/matrix interface interaction fractograph of tensile and impact tested samples.

Carbon fiber lumbopelvic reconstruction following sacral giant cell tumor resection: illustrative case.

The use of carbon fiber or polyetheretherketone spine constructs has proven to be a safe and effective alternative to standard metal alloy. The mechanical properties of carbon fiber while unique provide a construct that is comparable in strength to previous titanium-based constructs and have additionally shown greater fatigue resistance. These constructs have been especially useful for the mechanical stabilization of the spine following tumor resection. The subsequent interference seen when imaging a patient with a traditional metallic construct is reduced and allows for improved tumor surveillance after the procedure, and a more accurate delivery of radiotherapy when indicated. This case report details the treatment of a 25-year-old female diagnosed with a sacral giant cell tumor. The authors discuss the use of a carbon fiber-reinforced polyetheretherketone for lumbopelvic reconstruction. Carbon fiber-reinforced polyetheretherketone with its radiolucency and rigidity is a reliable option for complex spinal reconstruction after tumor resection.

Effect of Cu coating thickness on carbon fiber surface on microstructure and mechanical properties of carbon fiber reinforced aluminum matrix composites

Effect of Cu coating thickness on carbon fiber surface on microstructure and mechanical properties of carbon fiber reinforced aluminum matrix composites

Various mechanical tests of carbon fiber monofilaments

In recent years, in order to accurately predict the mechanical properties of carbon fiber-reinforced plastic by computer-aided engineering, it has become important to understand the mechanical properties of carbon fiber as a reinforcement material. Since carbon fiber is a material whose properties are highly anisotropic, information on tensile properties only in the axial direction of the fiber is not sufficient for predicting composite properties, and tests to obtain properties in various directions are desired. This paper discusses the anisotropy of carbon fibers by presenting the results of our previous tests on carbon fiber monofilaments, including observation of the changes in fiber diameter, dynamic and static torsion tests, torsion-tension tests, transverse crush tests, axial compression tests and three-point bending tests, and finite element method analysis using elastic moduli obtained from these tests.

A deep learning convolutional neural network and multi-layer perceptron hybrid fusion model for predicting the mechanical properties of carbon fiber

Recently, deep learning methods have become one of the hottest topics in predicting material properties, however, one bottleneck in current research is the simultaneous analysis of heterogeneous data. In this study, a deep learning fusion model is developed for the first time to predict the material properties of carbon fiber monofilament using textual (macroscopic properties of composites and matrix) and visual (two-point statistics of microstructures) data. For this, 1200 stochastic microstructures are generated using the greedy-based generation (GBG) algorithm. Then, the statistical representations of microstructures are determined using two-point statistics and the macroscopic properties are calculated based on a micro-scale finite element (FE) simulation. Finally, the visual and textual data are fed into the convolutional neural network (CNN) and multi-layer perceptron (MLP) fusion model for predicting the mechanical properties of carbon fibers. The developed hybrid CNN-MLP fusion model achieves encouraging average testing R2 of longitudinal modulus, transverse modulus, in-plane shear modulus, major Poisson’s ratio, and out-of-plane shear modulus of carbon fibers with values of 0.991, 0.969, 0.984, 0.903, and 0.955, respectively. Thus, the proposed strategy provides a promising framework for predicting material properties via multisource heterogeneous data and is expected to accelerate the smart design and optimization of materials.

Improved the interfacial characteristics of carbon fiber/polyamide 6 composites by synthesizing polydopamine rapidly on the carbon fiber surface with ultrasound-assisted

Poor interfacial compatibility is the main factor restricting the improvement of mechanical properties of carbon fiber (CF) reinforced polyamide 6 (PA6) composites. In this paper, we exploited the feature that polydopamine (PDA) can be rapidly synthesized under hypoxic conditions by ultrasound, and the PDA coating was generated quickly and uniformly on CF to modify the interface of the composites. The results show that CF could be entirely coated by impregnating CF in PDA-Tris solution for 1 h under the ultrasound. The introduction of PDA coating significantly enhanced the wettability of the CF surface. The application of ultrasound greatly improved the coating efficiency of PDA on CF, especially on the inner layer of the CF bundle. Compared with desized CF/PA6 composites, the interlaminar shear properties of PDA-modified CF/PA6 composites are improved by 21.07%. The PDA coating binds well to both CF and PA6, so when the composites were exposed to shear force, the interlayer cracks spread along the PDA and PA6 layers instead of the CF surface, resulting in greater resistance to crack propagation. It is the primary reason for improving the composites’ interface performance. Therefore, ultrasound-assisted rapid synthesis PDA on CF can effectively improve the interface characteristics of CF/PA6 composites.