Heterocyclic aramid fibers, a typical kind of high-performance fibers, have been widely used in aerospace and protection fields because of their excellent mechanical properties. However, the application of heterocyclic aramid fibers as a reinforcement is hindered by the weak interfacial combination with matrix materials, especially epoxy. Traditional strategies enhancing the interfacial shear strength (IFSS) usually decrease the tensile strength. Therefore, simultaneous enhancement of both mechanical properties remains a challenge. Herein, we report a novel heterocyclic aramid fiber with high interfacial shear strength (49.3 MPa) and tensile strength (6.27 GPa), in which 4,4′-diamino-2′-chlorobenzanilide (DABA-Cl) and a small amount of graphene oxide (GO) are introduced through in-situ polymerization. Hydrogen bonds and π–π interaction between GO and polymer chains trigger the enhancement in crystallinity, orientation, and lateral interaction of the fibers, thus improving the tensile strength and interfacial shear strength of the fibers. Moreover, the interfacial interaction between fiber and epoxy is enhanced due to the improvement of the surface polarity of the fibers caused by DABA-Cl. Therefore, a method to improve both tensile strength and interfacial shear strength of heterocyclic aramid fibers was found by introducing GO and DABA-Cl, which may provide guidance for the design and preparation of other high-performance fibers.

杂环芳纶纤维是一种典型的高性能纤维，因其优异的机械性能而广泛应用于航空航天和防护领域。然而，杂环芳纶纤维作为增强材料的应用受到与基体材料（尤其是环氧树脂）的弱界面结合的阻碍。提高界面剪切强度（IFSS）的传统策略通常会降低拉伸强度。因此，同时增强两种机械性能仍然是一个挑战。在此，我们报道了一种具有高界面剪切强度（49.3 MPa）和拉伸强度（6.27 GPa）的新型杂环芳纶纤维，其中通过原位引入4,4'-二氨基-2'-氯苯甲酰苯胺（DABA-Cl）和少量氧化石墨烯（GO）聚合。GO与聚合物链之间的氢键和π-π相互作用引发纤维结晶度、取向和横向相互作用的增强，从而提高纤维的拉伸强度和界面剪切强度。此外，由于DABA-Cl改善了纤维的表面极性，增强了纤维与环氧树脂之间的界面相互作用。因此，通过引入GO和DABA-Cl，找到了一种同时提高杂环芳纶纤维拉伸强度和界面剪切强度的方法，这可以为其他高性能纤维的设计和制备提供指导。