Abstract Carbon fiber/PEEK composites have gained significant attention in the field of continuous carbon fiber reinforced polymers (CFRPs). However, it remains challenging to improve the weak interfacial strength between carbon fiber (CF) and PEEK matrix. In this paper, strong interactions at the interface of sizing agent and carbon fiber were effectively achieved by introducing chemical bonds. Specifically, a soluble PEEK sizing agent where aniline served as pendant group and phenylacetylene served as blocking agent was synthesized. In the meantime, the phenylacetylene group was grafted on the carbon fiber surface through electroreduction. Then, the soluble sizing agent was used to size the electrochemical treated carbon fiber. After the heat treatment, chemical bonds were established by the crosslinking reaction of phenylacetylene groups existed in both the surface of carbon fiber and sizing agent. Meanwhile, the crystalline structure in the sizing layer was remained, which could improve the toughness of the interphase. As a result, the interfacial shear strength (IFSS) increased by 137.5% from 43.4 MPa of the untreated carbon fiber (U-CF) to 103.1 MPa of the reductive electrografted and coated carbon fiber (E-C-CF). The interlaminar shear strength (ILSS) also increased by 66.8% from 58.4 MPa of untreated CF/PEEK composites (U-CF/PEEK) to 97.4 MPa of reductive electrografted and coated CF/PEEK composites (E-C-CF/PEEK). The outstanding performances could be attributed to better compatibility of sizing agent and most importantly, the existence of chemical bonds between the carbon fiber and sizing agent.

中文翻译：

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电化学接枝与可交联结晶施胶剂协同提高碳纤维/PEEK复合材料的界面强度

摘要 碳纤维/PEEK复合材料在连续碳纤维增强聚合物（CFRPs）领域受到了广泛关注。然而，改善碳纤维 (CF) 和 PEEK 基体之间的弱界面强度仍然具有挑战性。本文通过引入化学键有效地实现了上浆剂与碳纤维界面处的强相互作用。具体而言，合成了以苯胺为侧基、苯乙炔为封端剂的可溶性PEEK施胶剂。同时，苯乙炔基团通过电还原接枝在碳纤维表面。然后，使用可溶性上浆剂对电化学处理的碳纤维进行上浆。热处理后，化学键是通过存在于碳纤维和上浆剂表面的苯乙炔基团的交联反应建立的。同时，上浆层中保留了晶体结构，可以提高界面相的韧性。结果，界面剪切强度 (IFSS) 从未经处理的碳纤维 (U-CF) 的 43.4 MPa 增加到还原电接枝和涂层碳纤维 (EC-CF) 的 103.1 MPa，提高了 137.5%。层间剪切强度 (ILSS) 也从未经处理的 CF/PEEK 复合材料 (U-CF/PEEK) 的 58.4 MPa 增加到还原性电接枝和涂层 CF/PEEK 复合材料 (EC-CF/PEEK) 的 97.4 MPa，提高了 66.8%。优异的性能可归功于施胶剂更好的相容性，最重要的是，