Wettability Of Carbon Fibers Research Articles

Advances in constructing Carbon Fiber‐MXene multilevel structures to reinforce interfacial properties of carbon fiber reinforced polymer composites

AbstractCarbon fiber reinforced polymers (CFRPs) have received widespread attention due to their excellent mechanical properties. However, the poor interfacial properties between CF and resin matrix urgently need feasible and efficient surface modification strategies of CF to regulate the interface. Due to its unique layered structure and abundant surface groups, MXene has been increasingly used in the field of CFRP interfacial modification in recent years. It possesses the advantages of good stability, large specific surface area, abundant adsorption sites and rich functional groups, which could effectively improve surface polarity, roughness and wettability of carbon fibers, thus enhancing effective interfacial bonding and enabling hierarchical regulation of interface in CFRPs. This paper reviews feasible strategies for constructing CF‐MXene multilevel structures, including electrophoretic deposition, chemical grafting, electrostatic self‐assembly, and sizing coating. Then, the strengthening mechanism involving surface morphology, mechanical properties, and interfacial strength of CFRPs are systematically evaluated centered on interfacial activity, interfacial adhesion, surface roughness and surface energy. Meanwhile, the problems in introducing MXene to CF surfaces and future research directions are systematically prospected. This paper could provide valuable guidance to construct CF‐MXene multilevel structures to reinforce interfacial properties of CFRPs composites, thus realizing hierarchical modulation of CFRPs interfaces.Highlights A feasible strategy for constructing CF‐MXene multilevel structures is built. The main methods for constructing CF‐MXene multilevel structures are provided. Treatment processes and reinforcing mechanisms of CFRPs are evaluated.

Recovery of carbon fiber from carbon fiber reinforced polymer waste via microwave molten-carbonate pyrolysis

In recent years, the increased use of carbon fiber-reinforced polymer (CFRP) composites has led to a significant rise in waste production. To address this issue, a recycling method using microwave molten salt pyrolysis-oxidation has been proposed to efficiently process CFRP and obtain regenerated carbon fibers (RCFs) under the combined effect of microwave and Na2CO3/K2CO3/Li2CO3 composite molten salt. The mechanism of microwave molten salt pyrolysis was examined in conjunction with the pyrolysis products (pyrolysis oil and gas), furthermore, the microwave molten salt pyrolysis process was optimized. The causes of the changes in the mechanical characteristics and wettability of carbon fibers (CFs) were additionally investigated and analyzed. The RCFs recovered from previous composite materials were processed into new composite materials and mechanically tested to assess their reusability. The study found that using microwave pyrolysis at 350°C for 10 min followed by oxidation at 450°C for 20 min resulted in recovered carbon fibers (RCFs) that retained 98.81 % of the tensile strength of the virgin carbon fibers (VCFs). Additionally, the RCFs showed a tensile modulus enhancement of 14.70 %, with the recovery ratio of carbon fibers as high as 98.44 %. Pyrolysis generates combustible gases like hydrogen (H2), carbon monoxide (CO), and alkanes, alongside products primarily composed of phenols and aromatic compounds. The recycling method can quickly recover high-performance carbon fibers and valuable pyrolysis by-products from CFRP waste, making them highly valuable for resource recycling and the sustainable development of carbon fiber materials.

Enhancing the mechanical properties of CF-reinforced epoxy composites through chemically surface modification of carbon fibers via novel two-step approach by addition of epichlorohydrin

The chemical surface modification was carried out in this study to improve the interface connection between carbon fiber (CF) and epoxy matrix to study the mechanical and fracture behavior of CF-reinforced epoxy composites. Finite element analysis was carried out by using ABAQUS software to simulate the variation of the tensile strength (TS), interfacial shear strength (IFSS), and interlaminar shear strength (ILSS). The chemical surface modification was carried out by the chemical oxidation by nitric acid and subsequently, addition of monomer resin of epichlorohydrin in a solution at 80 °C. The Raman spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy were carried out to ensure the successful surface modification of CFs. Subsequently, surface-modified CF-reinforced epoxy composites were prepared through the hand lay-up method with the volume fraction of 20 wt.%, and curing was carried out at 80 °C for 4 h. The TS, IFSS, and ILSS values equaled 462.82 MPa, 156 MPa, and 4.1 MPa for modified CF/epoxy composites were achieved, respectively, which are improved remarkably compared to unmodified ones (380, 81, and 2.9 MPa). These improvements are attributed to the successful surface modification of CFs by epichlorohydrin. The surface modification causes the increase in wettability of CFs and the formation of mechanical interlocking and interaction between CFs and epoxy matrix was achieved through uniform and homogenous distribution of epichlorohydrin on the surface of CFs. Fractography was carried out, which indicated the sound and uniform adhesion between CF and epoxy matrix. Achieved results are consistent with simulated results.

Bio‐based semi‐aromatic waterborne PIEK‐C sizing agent to construct a robust interface for CF/PEEK composites

AbstractDespite the impressing advances on sizing agents for CF/PEEK composites, the aromatic backbone of the polymer precursors utilized in the vast majority of reports compromises the dispersity and ductility of the slurry, subsequently resulting in inferior overall performance of the composites. Meanwhile, most resins employed for sizing agents in existing reports are based on petroleum resources. Herein, a bio‐based waterborne sizing agent utilizing semi‐aromatic poly ether ketones (PIEK‐C) derived from isosorbide and phenolphthalein has been disclosed, featured by its salutary dispersity, exceptional thermal stability, higher glass transition temperatures, and broader applicability. Due to the structural similarity between the sizing and resin matrix, the protocol endowed CF/PEEK composites with ameliorated overall performance, addressing issues related to inadequate adhesion of CF with PEEK resin, as well as environmental pollution commonly associated with existing commercial epoxy and solvent‐based sizing agents. The Tg and T5% of PIEK‐C‐5050 were 205.08 and 427.16°C, respectively. The particle size range of the PIEK‐C sizing agents spanned from 66.32 to 84.63 nm. The flexural strength and interlaminar shear strength of the composites experienced a respective 993.92 MPa (30.73%) and 83.32 MPa (36.97%) increase compared to untreated CF/PEEK composites following sizing treatment with PIEK‐C‐5050, underscoring expedient intermolecular interactions based on comparable solubility and π‐π stacking effects between the PEEK and PIEK‐C components. This study introduced an efficient and eco‐friendly approach to enhance the interfacial properties of CF/PEEK composites.Highlights PIEK‐C resin is employed for the first time to prepare carbon fiber sizing agents. The PIEK‐C sizing agent significantly fortified the surface energy and wettability of carbon fibers. The CF/PEEK composites after treatment with PIEK‐C sizing agent showed excellent heat resistance. The ILSS and bending strength of the composites were significantly increased by 36.97% and 30.73%, respectively.

Construction of polydopamine functionalized porous carbon network structure in polymer composites for excellent mechanical and electromagnetic interference shielding properties

Structural and functional integrated lightweight polymer-based composites with excellent mechanical and electromagnetic interference (EMI) shielding properties are urgently demanded in the field of advanced aerospace field. Effective design to construct the interfacial porous microstructures is crucial yet remains highly challenging for maximum EMI shielding effectiveness (SE) while improving the strength of composites. Herein, novel interfacial continuous network structures are constructed based on the in-suit synthesis of porous carbon network on the carbon fibers and chemical functionalized with polydopamine (PDA) to achieve simultaneous improvement of mechanical properties and EMI SE. Results indicate that the construction of active porous carbon networks significantly improves the surface activity and wettability of carbon fibers, which is conducive to enhancing the interfacial strength of the composites. Owing to the synergistic effect of physical enhancement for porous carbon and chemical reinforcement for PDA, the bending strength of the modified composite reaches 138.9 MPa, and the wear rate decreases by 82.9 %, demonstrating excellent mechanical properties. It is worth noting that the EMI SE reaches more than 62 dB in the X-band when the thickness of the modified composite is only 0.4 mm, showing excellent EMI shielding performance. Most importantly, this study provides solid basic knowledge of the interfacial structure design of composites, which is favorable for obtaining expected mechanical and EMI shielding performances and offers strong potential for applications in structural components of the aerospace and electronic equipment field.

Modified mechanical properties of carbon fiber/epoxy composite by silicone polymer

AbstractIn this work, silicone polymer (PSOL)/carbon fiber (CF)/epoxy (EP) composites were prepared by introducing PSOL as interfacial modifiers into CF/EP composites. The mechanical and dynamic mechanical properties of the composites were investigated, and the optimum content of the PSOL modification was obtained. The impact of EP on the wettability of CF was compared before and after adding PSOL. The micromorphology of CF/EP composites was also observed. The consequences demonstrate that the interfacial bonding ability between CF and matrix was improved after adding PSOL. The interlaminar shear strength, tensile strength, elongation at break and flexural strength of PSOL/CF/EP composites were increased by 23.28%, 18.49%, 38.45% and 11.23%, respectively. Furthermore, the original thermal stability of the composite was preserved after the modification of PSOL.

Effect of graphite oxide content on shape memory performance of graphite oxide‐carbon fiber hybrid reinforced shape memory polymer composites by VIHPS

AbstractGraphite oxide (GO)‐carbon fiber (CF) hybrid reinforced shape memory polymer composites (SMPC) with different GO content were prepared by vacuum infiltration hot‐press forming experimental system (VIHPS). By studying the wettability and adhesion characteristics between the shape memory matrix and CF, it was found that the addition of GO could improve the ability of the matrix to wet the CF surface and enhance the interface bonding. The shape memory performance of the composite with GO was better than that of CF reinforced epoxy matrix composite. The shape fixed rate increased by nearly 8%, and the shape recovery rate increased by nearly 13%. Combined with the test results and the characterization analysis of microstructure, the strengthening effect of GO was mainly reflected in the following aspects. Firstly, the surface folds of GO and its two‐dimensional grid structure increased the surface roughness and wettability of CF, forming a mechanical interlock among GO, reinforcement and matrix. The mechanical interlock promoted the reinforcement and matrix to have an ideal interfacial bonding strength. Secondly, the addition of GO was conducive to the transfer of deformation force and heat to prevent stress concentration in the composite and significantly improved the shape memory performance of the composite.

Hybridization of carbon fiber composites with graphene nanoplatelets to enhance interfacial bonding and thermomechanical properties for shape memory applications

ABSTRACT Shape memory polymer composite (SMPC) exhibits the remarkable mechanical properties as compared to its corresponding shape memory polymer (SMP) without compromising the shape memory behavior. The enhancement of the mechanical and thermomechanical properties of the carbon fiber-reinforced SMPC is presented in the present study with the incorporation of graphene nanoplatelets (GnP) in the SMP matrix. The fabrication process involved the preparation of the GnP/epoxy nanocomposites through ultrasonication and shear mixing and the subsequent molding of the carbon fiber-reinforced hybrid polymer composites by hand layup technique. The mechanical and thermomechanical characterizations were conducted as per the ASTM standards, which were followed with corresponding morphological study to the explore the microscale behavior of the hybrid composites. Shape memory behavior were studied in terms of the shape recovery () and shape fixity () through the heat activation bending tests. The tensile strength of the hybrid composites with 0.4 and 0.6 wt% GnP content increased by 14.3% and 32.2%, respectively, as compared to unmodified SMPC. Similar trends were also indicated in the dynamic mechanical analysis (DMA) with the corresponding rise in the storage modulus and glass transition temperature due to incorporation of nanofillers. The improvement of the interfacial bonding between the fiber and matrix and wettability of carbon fiber supported these improvements. Negligible adverse effect was noticed in the shape memory behavior of the hybrid composites with the incorporation of GnP, which displayed the and of ~97% and 96%, respectively.

Study on preparation and mechanical properties of bionic carbon fiber reinforced epoxy resin composite with eagle feather structure

Inspired by the effect of angle between feather shaft and the feather vane on strength enhancement of feather structure, carbon fiber reinforced epoxy resin composites with eagle feather structure were prepared successfully. Based on liquid-phase oxidation, wettability of carbon fiber was improved, which enhanced bonding strength between reinforcement and matrix and built material base for mechanical strength of bionic composite. With the increase of carbon fiber content (0.1 wt.%, 0.2 wt.%, 0.3 wt.% and 0.4 wt.%), tensile strength and impact toughness of carbon fiber reinforced epoxy resin composites increased first and then decreased. Composites with 0.2 wt.% carbon fiber exhibited optimal mechanical properties, which was used for preparation of bionic composite. Compared with carbon fiber reinforced epoxy resin composite with the traditional vertically arranged structure, the composite material with the bionic structure owned higher tensile strength and impact toughness. The fracture and drawing out of carbon fiber and crack deflection were mechanical mechanism of bionic composite, which provided a new design and preparation method for carbon fiber reinforced epoxy resin composite.

Improving Interfacial Interactions of CF/PEEK Composites with Sulfonated Polyether Sulfone

Due to the limitation of surface inertness and wettability of carbon fibers (CF), the adhesion between Poly(ether-ether-ketone) (PEEK) resin matrix and CF is poor, which reduces the mechanical properties of CF/PEEK composites. In order to improve the interfacial performance between PEEK matrix and carbon fiber fabric, sulfonated-polyether-sulfone (s-PSF) was coated as a sizing agent on the surface of the carbon fiber to construct CF/PEEK composite interface. On one hand, the formation of hydrogen bonds between s-PSF and activated CF increases the adhesion between s-PSF and fibers. On the other hand, Good compatibility between S-PSF and PEEK, which improves the interface performance between PEEK and CF. The results showed that the mechanical properties and interface properties of CF/PEEK composite prepared by modified CF were improved to some extent. The flexural strength, flexural modulus, impact strength and interlaminar shear strength of the materials were increased by 57.5 %, 16.7 %, 44.2 % and 39.7 %, respectively. By introducing s-PSF as sizing agent into CF/PEEK composite interface, the comprehensive properties of the material were effectively improved.

Enhancement of thermal stability and wettability for epoxy/Cu coated carbon fiber composites

This research study the effect of surface modification and copper (Cu) plating carbon fiber (CF) surface on the thermal stability and wettability of carbon fiber (CF)/epoxy (EP) composites. The TGA result indicates that the thermal-stability of carbon fiber may be enhanced after Cu coating CF. TGA curve showed that the treatment temperature was enhanced thermal stability of Ep/CF, this is due to the oxidation during heating. The Cu plating increased the thermal conductivity, this increase might be due to reduce in contact resistance at the interface due to chemical modification and copper plating and tunneling resistance.
 The increase of surface polarity after coating cause decrease in the value of contact angle. As well as the increase of CuO as a function of the heat temperature cause the rapid contact angle decrease and can strongly enhance the wettability.

Wettability of thermoplastic and thermoset polymers with carbon nanotube grafted carbon fiber

In this experimental study the wetting behavior of unsized and carbon nanotube (CNT) grafted carbon fibers is assessed with various polymers. Thermoset epoxy and two thermoplastics (polypropylene and polycarbonate) are tested. Sessile drop method and drop-on-fiber method are employed to quantify the wettability of various fiber/polymer combinations. Contact angle measurements based on the above two methods give insights into the effectiveness of various polymers to wet different types of carbon fiber fabrics and single fiber filaments. Moreover, the effect of CNT length and density on the wettability of carbon fibers is ascertained by synthesizing nanotubes on the fiber surface for varying time durations (10–30 min). CNT grafting reduces the contact angle of the polymer drop with carbon fiber; however, too much growth of nanotubes on the fiber surface leads to improper impregnation of the polymer into the carbon fabric. While polypropylene shows better wetting characteristics with unsized and CNT grafted carbon fibers, polycarbonate shows poor wettability.

Molecular Structure Design of Sizing Agent and Its Influence on the Mechanical Properties of CF Reinforced Composite

In this article, phosphate modified epoxy resin (PAEK) and polyethylene oxide (PEO) were used as the main monomers to fabricate a composite sizing agent (TPP) for carbon fiber (CF) surface treatment. The effects of TPP sizing on the surface morphology, activity and wettability of CF were studied by FE-SEM, XPS and contact angle. In addition, friction coefficients, fuzz amount and the mechanical properties of CF filaments, as well as the interlaminar shear strength (ILSS) of CF composites were analyzed. The results indicate that the defects of CF surface were completely repaired by TPP molecules, the content of active groups increased by 24.8 % and the contact angle and the spreading time of EP on CF surface reached respective minimum values of 43.5 ° and 15 s, meanwhile, the friction coefficient and the fuzz amount of the treated CF surface are reduced in the sizing quantity range of 3.0–4.0 mg/g. Thus, there were 36.1 % and 24.3 % enhancement in the breaking strength and elongation of CF filament. In addition, the ILSS of composite prepared with TPP treated CFs was increased from 12.81 to 28.55 MPa.

Interfacially reinforced unsaturated polyester carbon fiber composites with a vinyl ester-carbon nanotubes sizing agent

A amino-functionalized carbon nanotubes (CNTs)-containing sizing agent was prepared for improving the interface bonding and impact toughness of carbon fibers (CFs) reinforced unsaturated polyester (UP) composites. More reactive groups and better interfacial compatibility with UP make vinyl resin M7270 a more suitable polymer for preparing sizing agent for CF/UP composites when compared to epoxy, MR13006 and R806. The surface characteristics of CFs and the interfacial properties of the composites before and after surface modification were investigated. The observed uniformly dispersed CNTs-containing sizing agent on the CF surface obviously increased the surface roughness. The amount of polar functional groups and the wettability of CFs were significantly enhanced after the coating treatment. The interlaminar shear strength (ILSS) and impact toughness were enhanced by 32.3 and 55.2%, respectively. The sizing agent effectively enhanced the interfacial adhesion by improving the surface energy, and increasing chemical bonding and mechanical interlocking.

A facile and scalable coating technique of carbon fibers with carbon nanoparticles for surface adhesion enhancement of fibers and resin in 2D C/C composites

Abstract In order to improve mechanical properties of 2D carbon-carbon composite via increasing fiber/matrix interfacial adhesion, we have developed a simple, low cost and scalable method for carbon fibers (CFs) coating. This method is inspired to ink printing process in which pigments/dyes are transferred and set on the different surfaces via proper chemical bindings. For this purpose, we have used colloidal suspension of carbon nanoparticles in printing ink solution and coated the surfaces through dip-coating procedure. The results of SEM observations showed that colloidal suspension of nano-carbon particles in ink solution could be successfully used as a coating solution for preparing a uniform, well distributed and defect-free coating. Also water wettability measurement test has been conducted in order to evaluate the carbon coating on the surface chemistry of carbon nanofibers. The results revealed significant improvement on wettability of CFs after coating owing to abundant hydrophilic groups introduced from ink solution onto the surface of CFs (approved by FTIR spectroscopy). Finally, the mechanical properties of 2D C/C composites prepared by as-received and nano-coated CFs have been evaluated. The result of mechanical properties showed remarkable improvement in both flexural and shear strength of final composite by 15% and 18%, respectively.

Wettability of carbon fibres at micro- and mesoscales

Physical adhesion between Carbon Fibres (CFs) and polymer matrices as well as the formation of voids at the interface between these two materials are mostly controlled by the wetting properties of the fibres. Due to the hierarchical structure of CF reinforcements, it is essential to study their wetting behavior at different scales: from the single fibre (microscale) to the fabric (macroscale) via the tow scale (mesoscale). Probing the wettability of CF tows is, however, highly challenging, because it couples the effects of surface chemistry and geometry of the fibre assembly characterized by spontaneous capillary wicking and elasto-capillarity induced aggregation. Therefore, we first developed a new methodology combining a tensiometric method and a synchronized in-situ optical observation technique to better characterize the wettability of CF tows. We then used it to evaluate the difference in wettability between tows composed of unsized and sized (T300) CFs. By comparing their wettability at the micro- and mesoscale, we could quantify how the modification of the surface chemistry at the microscale is transferred to the mesoscale.

Electroplated Connections Between Carbon Fiber and Nickel

Carbon has become an attractive material for electronic packaging applications, such as interconnects, because of its low density and reasonable electrical conductivity. One challenge in these applications is overcoming the inherent chemical incompatibility between carbon and metals that limits adhesion. Recently, we explored a new technique for electroplating carbon fibers with nickel. Electroplated carbon fiber tows were soldered to nickel metal tabs using SAC 305 (Sn3Ag0.5Cu). The electroplated nickel was found to be free of microvoids with (Ni,Cu)3Sn4 forming as intermetallic compounds (IMCs) in an annular region presumed to be Ni3Sn4 at the SAC 305-Ni interface. Mechanical characterization of the carbon fiber–nickel interface revealed bond strengths up to 434 N, which is similar to a 22 gauge high strength copper clad steel. Electrical resistances were found to be as low as 1.1 Ω for a 38.1 mm long connection. Carbon–metal connections prepared using silver epoxy were found to have 80% lower load bearing capacity and 10–20% higher electrical resistance. Battery discharge tests indicated that the carbon connections reduced performance by only 4% compared to conventional copper. The performance drop increased to 7% when the discharge time was increased by 50%, indicating some thermal dependence. The electroplating technique is a fairly simple and inexpensive means of enhancing the wettability of carbon fiber to create scalable carbon-based conductors for low current systems.

Interfacial microstructure and mechanical properties of carbon fiber composites by fiber surface modification with poly(amidoamine)/polyhedral oligomeric silsesquioxane

Polyhedral oligomeric silsesquioxane (POSS) was grafted onto carbon fiber surface using poly(amidoamine) (PAMAM) as a novel coupling agent at mild reaction conditions. Firstly, the reinforcement was designed with propagation of PAMAM on the fiber surface by in situ polymerization to improve the surface activities of carbon fiber. Secondly, the POSS further grafted on the fiber could significantly enhance fiber surface energy and wettability, which would greatly increase the interfacial strength of fiber-matrix. The microstructure and mechanical properties of carbon fiber and the resulting composites were investigated. The results indicated that PAMAM and POSS, which could significantly increase the surface roughness and wettability of carbon fiber, were successfully grafted on the fiber surface. Compared with the desized fiber composites, the interlaminar shear strength and the interfacial shear strength of the modified carbon fiber composites increased by 48% and 89%, respectively.

Effects of grafting low-generation poly(amido amine) onto carbon fiber surface by in situ polymerization on the mechanical properties of fiber composites

Low-generation poly(amido amine) (PAMAM)-grafted carbon fibers (CFs) emerged as a new reinforcement for improving the mechanical properties of fiber composites. In this work, hybrid reinforcement, which could greatly enhance the surface roughness and wettability of CF, was prepared via growing PAMAM onto fiber surface by in situ polymerization.The modified surface morphology and chemical composition were investigated by scanning electron microscopy, atomic force microscopy, dynamic contact angle analysis test, and X-ray photoelectron spectroscopy. Experimental results indicated PAMAM dendrimers grown on the CF significantly enhanced interfacial properties of the resulting composites. In addition, compared with the desized CF composites, the CF grafted with PAMAM composites exhibited 34.65% enhancement in the interfacial shear strength.

Effect of Coating Parameters on Coating Rate of Carbon Fibers by Electroless Nickel Plating

The coating quality of nickel is important factor in improvement of wettability of carbon fibers to be used as reinforcing material in the production of carbon fiber reinforced metal matrix composites. In this research work, Polyacrylonitile (PAN) based carbon fibers have been Ni coated in Sodium hypophosphite reduced acidic bath by electroless plating method. These carbon fibers are coated using 4, 4.5, 5 and 5.5 pH values for 5, 10, 15, 20, 25 and 30minutes. Coating thickness is found to increase with time linearly. Nickel deposition rate per unit time increases with pH, however it reaches a maxima and then declines. The surface condition of fibers reveals that coating becomes more and more rough due to non uniform coating, as coating time and pH goes on increasing.