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Highlights Zeolitic imidazolate framework‐8 (ZIF‐8) was used to enhance the interfacial strength of composites due to its large specific surface area, uniform pore size, and high stability. Morphology‐controllable ZIF‐8 nanocrystals were synthesized by solvent method and a layer of small‐sized and height crystalline ZIF‐8 was deposited on carbon fibers via an efficient electrophoretic deposition (EPD) way. The results showed that interlaminar shear strength (ILSS) and tensile strength (TS) of carbon fibers/epoxy composites and the TS of carbon fiber were enhanced by 43.56% and 25.48%, respectively. The strong interfacial adhesion strength between carbon fibers and epoxy was attributed to improving the wettability, ionic interaction and the mechanical interlocking effect induced by porous ZIF‐8, which led to effective energy absorption and load transfer. This highly efficient and controllable method is believed to improve the mechanical properties of carbon fiber composites for a wide range of industrial uses. ZIF‐8s in different sizes and morphology were synthesized by solvent method. MOF was deposited firstly onto carbon fibers though electrophoretic deposition. Materials Studio was used to evaluate the strong anchoring strength. ILSS of composites was enhanced by 43.56%. [ABSTRACT FROM AUTHOR]

Various sizing agents were prepared to enhance the interfacial properties between aramid fiber (AF) and polycarbonate (PC), as well as to enhance the mechanical properties of AF/PC composites. It was found that PC sizing agent, P‐GO sizing agent, and PSi‐GO sizing agent effectively coated the surface of AF from the FTIR and XPS and SEM results. The IFSS and mechanical properties of composites reinforced with fibers treated by the sizing agents exhibited significant improvement, as well as their single fiber tensile strength also improved. Specifically, when AF was treated with PSi‐GO sizing agent, the interfacial shear properties between AF and PC increased by a remarkable 78.69%, reaching 22.89 MPa compared to the original AF/PC composite, the tensile strength of the single‐filament exhibited an increment of 12.4% to 26.4 cN/dtex. Moreover, the tensile strength, flexural strength, and impact strength of the composite increased by 5.43%, 77.74%, and 54.71%, respectively. These improvement can be attributed to the GO with a higher concentration of chemical groups and excellent dispersion with modified with the silane agent. These findings suggest that coating the AF with sizing agents can effectively enhance its interfacial adhesion with the matrix, which is useful for its application as the reinforcement in the composites. Highlights: Adding GO to the sizing agent to change the Aramid fabric surface properties.Silane coupling agent was used to improve the dispersion of GO on the fiber surface.GO modified sizing agent can improve the flexural strength, tensile strength, and interlaminar shear strength of the composites. [ABSTRACT FROM AUTHOR]

The surface of carbon fiber is treated with sizing agent containing hydroxylated carbon nanotubes, fullerenols, and graphene oxide, respectively. The effects of carbon nanomaterials and their structures on the surface properties of carbon fiber, the interfacial properties and the mechanical properties of carbon fiber/epoxy composites are investigated. All three types of carbon nanomaterial can improve the interfacial bonding strength and modulus, thereby enhancing the interlaminar shear strength (ILSS) of composites. Moreover, the ILSS increases with the increase of interfacial bonding strength, due to the roughness and the number of active groups. Compared with the composite without carbon nanomaterials, the interfacial bonding strength of the three nanoparticle‐modified composites increased by 14%, 5% and 4%, the modulus increased by 10%, 26%, and 9%, and the ILSS increased by 14%, 8%, and 7%, respectively. The interfacial bonding strength has a more significant impact on the ILSS than the interfacial modulus. Highlights: CNTs, graphene oxide and fullerenols regulate the surface characteristics of carbon fibers.The influence of carbon nanomaterials on the interfacial properties of composites.The relationship between the fiber surface, the interface and the composites. [ABSTRACT FROM AUTHOR]

Highlights Two‐dimensional (2D) MXene (MX) and silane coupling agents are increasingly used to modify carbon materials for the fabrication of composite functional materials, which exhibit enhanced electrical, optical, and mechanical properties due to the synergistic effects of both MX and silane. We demonstrate the modification of carbon fibers (CFs) with MX and three different kinds of silane coupling agents, including 3‐aminopropyltriethoxysilane, 3‐glycidyloxypropyldimethoxymethylsilane, and 3‐mercaptopropyltriethoxysilane, which are named as CF‐MX@N, CF‐MX@O, and CF‐MX@S, respectively, and further prepare the CF‐MX@silane/epoxy (EP) composites. The utilized silane coupling agents serve as bridges between MX and CFs, forming CF‐MX@silane composites. Through comparative analysis, it is found that the CF‐MX@S composites form a strong interface phase through covalent bonds, significantly enhancing the interface compatibility and revealing strong interface adhesion. The interfacial shear strength of the molded CF‐MX@S/EP composites increases to 119.7 MPa, with an 173.9% enhancement comparing to unmodified composites. This work can offer useful guidance and reference for selecting appropriate silane coupling agent to modify CFs with 2D materials to form high‐performance composite materials. Silane coupling agents are used as bridges to graft MXene‐modified CFs The surface modification of CFs is achieved by a simple one‐step approach Excellent interfacial phase is constructed through forming strong covalent bonds Microstructure and failure interface are responsible to interface strengthen. [ABSTRACT FROM AUTHOR]

Highlights The impact of carbon fiber (CF) composites sizing with graphene oxide (GO) to form brick‐and‐mortar structures on their mechanical properties and thermal conductivity has not been closely examined. This study systematically investigates the effect of GO sheet size on the interfacial properties and thermal conductivity of CF composites. Three sizes of GO—small (0.11 μm), medium (0.33 μm), and large (0.97 μm)—were used to modify CF surfaces via layer‐by‐layer self‐assembly, forming the brick‐and‐mortar structures. The mechanical properties were assessed through flexural tests, interlaminar shear strength (ILSS) tests and tensile tests, while thermal conductivity was measured using a thermal constant analyzer. The results revealed that medium‐sized GO (GO‐M) significantly enhanced the interfacial strength and toughness of the composites. This improvement is attributed to the orderly arrangement of GO‐M on the CF surface, which enhances stress transfer between the fiber and the matrix. In contrast, small‐sized GO (GO‐S) tended to scatter, resulting in less effective reinforcement, while large‐sized GO (GO‐L) exhibited stacking and agglomeration, limiting its reinforcement effectiveness. However, GO‐L provided the highest thermal conductivity due to the formation of continuous heat conduction pathways. These findings suggest that GO‐M offers a balanced improvement in mechanical properties, whereas GO‐L is more suitable for applications requiring high thermal conductivity. This work underscores the importance of selecting the appropriate GO sheet size to optimize the interfacial properties and thermal conductivity of CF composites, which is crucial for enhancing their performance in high‐end engineering applications, such as aerospace, automotive, and marine industries. Modification of CF composites by GO‐M sheets significantly improved toughness and strength. GO‐L sheets formed an effective heat transfer channel with the highest thermal conductivity. The study emphasized the critical role of selecting the appropriate GO sheet size to optimize the mechanical and thermal properties of CF composites. [ABSTRACT FROM AUTHOR]

The application of carbon fiber (CF) in carbon fiber composites has faced limitations due to its surface chemical inertness. To overcome this challenge, this study draws inspiration from metal ion‐enhancing exquisite hierarchical and multiphase structures observed in biological materials. The research proposes a novel approach to enhance the interfacial bonding of CF/Epoxy (E‐51) composites by utilizing tannic acid (TA), carboxylated cellulose nanocrystals (CNCs), Fe3+ ions, and polyvinyl alcohol (PVA). This approach aims to create hydrogen bonding and metal synergistic networks on the surface of CFs through metal ion (Mn+) coordination cross‐linking synergistic (MCCS) interactions. Implementing MCCS strategy resulted in significant improvements in the mechanical properties of the hybrid reinforcements compared to untreated CF composites. The flexural strength, flexural modulus, interlaminar shear strength, and interfacial shear strength experienced respective increase of 50.9%, 72.8% 59.4%, and 61.9%. Moreover, the damping properties of the composites exhibited significant improvements. These positive outcomes can be attributed to the formation of chelation and dense hydrogen bonding networks between TA, Fe3+, CNC, and PVA. Furthermore, CNC and PVA formed cross‐linked nanolayers that effectively deflected cracks and facilitated high energy consumption at the interface. This proposed approach provides a sustainable, environmentally friendly, and efficient method for surface modification in the preparation of high‐performance fiber composites. Highlights: Metal ion (Mn+) coordination cross‐linking synergistic strategy is proposed.Tannins/Fe3+/CNCs/PVA form multiphase nanolayers.Metal ion coordination cross‐linking enhances delicate multiphase structures.The prepared carbon fiber composites exhibit excellent properties.The as‐prepared carbon fiber composite has promising applications. [ABSTRACT FROM AUTHOR]

This study reports the effect of graphene oxide (GO) coating on carbon fiber (CF) surface on the mechanical and thermal properties and morphology of CF‐reinforced polyamide 6 (PA6) composites containing 7.5 wt% of short CFs. GO was coated on the CF surface by a physical absorption method with concentrations ranging from 0.05 to 0.5 wt% GO. The PA6/CF composites were prepared by extrusion, and the specimens were obtained by injection molding. Their morphology (SEM, XRD tests), mechanical (tensile, flexural, impact, and fatigue tests), and thermal properties (DSC, TG and HDT tests) were analyzed. A significant change in the preferential (growth) crystal planes of PA6 was observed upon the incorporation of CFs containing GO, favoring the formation of α crystals in PA6. GO coating on CFs was effective and provided an increase in tensile strength and Young's modulus up to 12% and 24%, flexural strength and flexural modulus up to 22% and 25%, and a decrease in impact strength and fatigue life up to 30% and 23%, respectively, when compared to unmodified PA6/CF composites. Fracture micrographs indicated an increase in the PA6/CF interaction and the effectiveness of GO as a coupling agent for the composite. [ABSTRACT FROM AUTHOR]

In this study, the interfacial bonding properties of carbon fiber/polypropylene (CF/PP) composites fabricated by self‐resistance electric (SRE) heating technique was investigated by both experimental trials and molecular dynamic (MD) simulations. The temperature distribution and the changes in surface physical properties of CFs with SRE heating were firstly determined by experimental investigations. The experimental results suggest that the amount of grooves on CFs surface is positively related to electric current magnitude, while the height of grooves is negatively associated to electric current magnitude. The microbond test was carried out to determine the interfacial shear strength (IFSS) of CF/PP composites. It demonstrates that the IFSS increases from 31.00 to 39.11 MPa when CFs is applied with electric current from 12 A to 20 A, which is same with the trend of the surface area of CF. Moreover, the mechanisms of interfacial adhesion enhanced by surface morphology of CF were investigated by MD simulations. CF models with different surface morphology were constructed based on the experimental results. It is found that the increase of the contact area between CF atoms and PP atoms benefits the interfacial adhesion. Meanwhile, the gradual loss of the ability of matrix impregnation accompanies with the strengthening of interfacial interaction, leading to a weak increase in the shear strength between CF and matrix. [ABSTRACT FROM AUTHOR]

To enhance the interfacial adhesion of short carbon fiber (SCF) reinforced polypropylene (PP) composites, a new modified chlorinated polypropylene resin (g‐CPP) was synthesized and utilized to manufacture the sizing agent for SCF. The findings of thermogravimetric analysis and differential scanning calorimetry showed that g‐CPP had high thermal characteristics, with its glass transition temperature (Tg) raised by 11°C.The g‐CPP sizing agent that has been developed has increased storage stability (particle size was 109.8 nm). The contact angle of SCF was reduced from 81.52° to 60.04° after sizing, and the surface free energy was raised from 29.31 mN/m soared to 47.13 mN/m. The SCF/PP composites with 1 wt% sizing agent demonstrated the best interfacial adhesion, with improvements in flexural and tensile strengths of 54% and 39%, respectively. The interfacial reinforcement mechanism of sizing agent to improve interfacial adhesion was investigated. This work proposes an attractive way for the future preparation of high‐performance SCF/PP composites. [ABSTRACT FROM AUTHOR]

In the present study, the embedding ZnO nano‐whiskers (NWs) on carbon fiber (CF) surface was carried out to study the changes in Ohmic heating and mechanical stability of carbon fabric reinforced green epoxy composite laminates. The ZnO NWs were grown onto the CF surface by hydrothermal method and subsequently the laminate composites with different number of carbon woven layers were prepared. To study the resistive heating behavior of the laminate composites, the temperature versus time curves were analyzed in three sections, from which the temperature response rate, the maximum temperature, and the electrical power efficiency were estimated. Later, the effects of Ohmic heating action on the structural damage and mechanical stability of the composites were examined by dynamic mechanical analysis and X‐ray micro computerized tomography. Multilayer ZnO/carbon woven composites were found to be rapidly heating, less power consumption, and have improved mechanical and structural stability over bare carbon woven composites. This indicated that ZnO NWs enhanced the adhesion between the fibers and matrix, meanwhile acting as a heat barrier to avoid degradation of the epoxy at the interface of the fiber and matrix during Ohmic heating. [ABSTRACT FROM AUTHOR]

Pullout simulations were conducted to investigate the interfacial shear properties between defective graphene (DGr) and polymethyl methacrylate (PMMA) through molecular dynamics simulations with ReaxFF reactive force fields. The effects of number of defects (Stone‐Wales [SW] and double‐vacancy [DV] defects) were investigated. Our results showed that these two types of defects can obviously enhance the interfacial shear strengths of DGr /PMMA nanocomposites. And the DV defects have a greater contribution to the interfacial shear strength enhancement compared to the SW defects. Analysis of the morphology of DGr indicated that surface roughness, which was induced by defects, plays an important role in enhancing the interfacial shear strength at the interface between the DGr and PMMA. Moreover, the effects of chemical functionalization at the defect sites were also investigated. We observed that the CO bonds of functional groups (hydroxyls) at defect sites inclined from the datum plane (z = 0 plane) of the graphene sheet. The inclination of CO bonds, which weakened the mechanical interlocking between functional graphene and PMMA matrix, differently influenced by the DV defect and SW defect. [ABSTRACT FROM AUTHOR]