Constructing “nunchaku-like” multi-stage gradient interface via covalently grafting rigid-flexible-rigid structures onto carbon fibers: An effect strategy to improve interfacial properties of composites

To address the issue of inadequate interfacial adhesion in carbon fiber/poly ether ether ketone (CF/PEEK) composites, an innovative approach that combines carbene chemistry and sizing treatment was meticulously designed to achieve remarkable synergistic enhancement. Specifically, cyano groups were chemical‐grafted on CF surface via carbene reaction. Meanwhile, a water‐based self‐catalyzed cross‐linkable PENK‐NH2 sizing agent with good storage stability was prepared. Noteworthy, the presence of amino groups as blocking agents of sizing agent significantly accelerated the rate of cyano‐crosslinking, thus effectively avoiding the adverse effects of excessively prolonged cross‐linking period during composites preparation. As a result, robust interaction between cyano‐modified CF and PEEK was established by cross‐linking reaction, along with chemical bonds generated between amino groups of sizing agent and ketone groups in PEEK. The maximum interlaminar shear strength (ILSS) of CF‐CN‐1.5/PEEK composites was 22.0% and 57.0% higher than CF‐1.5/PEEK and CF/PEEK composites. Furthermore, the presence of cyano‐cross‐linked structure endowed interphase with outstanding solvent‐resistance, the mechanical properties of CF composites after solvent treatment were well‐preserved. The strong synergistic interfacial interactions facilitated by chemical bonds in different components provide an effective and fascinating methodology for producing high‐performance CF/composites.Highlights Water‐based self‐catalyzed cross‐linkable PENK‐NH2 sizing agents for CF/PEEK were prepared. NH2 was introduced to avoid the adverse effects of prolonged cyano‐crosslinking. Designed carbenoid motif with cyano group was grafted on CF via carbene chemistry. The interaction between sizing agent and CF was boosted by the cyano‐crosslinking. Mechanical properties of sized composites corroded by solvent were well‐preserved.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synergistic enhancement of interfacial adhesion for CF/PEEK composites through carbene chemistry and water‐based self‐catalyzed cross‐linkable PENK‐NH₂ sizing agent

Guo,

Pei,

Dai

et al. 2024

Bio‐inspired metal ion coordination cross‐linking synergistic strategy to enhance the interfacial properties of carbon fiber composites

Quan,

Wu,

Zhang

et al. 2023

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.

Simultaneous grafting of carbon nanotube and hyperbranched poly(thioether‐yne) onto carbon fiber via thiol‐alkyne click chemistry to improve interface properties of carbon fiber/epoxy composite

Xiong,

Liu

et al. 2023

An efficient and fast technique was proposed to graft carbon nanotube (CNT) on carbon fiber (CF) using hyperbranched poly(thioether‐yne) (HPTEY) as bridging agent through thiol‐alkyne click chemistry reaction. The successful synthesis of CNT/HPTEY grafted CF (CF‐HPTEY‐CNT) was verified with Fourier transform infrared, x‐ray photoelectron spectroscopy, thermogravimetric analyzer, and scanning electron microscopy. The simultaneous introduction of CNTs and HPTEY could significantly improve the wettability and surface energy of CF, leading to that the interfacial shear strength (IFSS) of CF‐HPTEY‐CNT/epoxy composite evaluated using the microdroplet test was remarkably enhanced by 106.4% than pristine CF/epoxy composite. The bending strength for CF‐HPTEY‐CNT/epoxy composite was also significantly increased by 40.4% because of the effective stress transfer at interface. Furthermore, the monofilament tensile strength of CF‐HPTEY‐CNT showed an increase (by 3.3%) as compared with pristine CF, attributed to that the grafting CNTs and HPTEY remedied the CF surface defects. Therefore, this work is expected to offer a promising technique for developing advanced structural composite with outstanding interface and mechanical properties.Highlights An efficient and fast technique to modify CF via click chemistry was proposed. The grafting of HPTEY‐CNT increased the surface roughness and wettability of CF. IFSS of CF‐HPTEY‐CNT/epoxy composite was significantly increased by 106.4%. The CF‐HPTEY‐CNT/epoxy composite had superior mechanical properties.