▎ 摘　　要

Poly(p-phenylene-benzimidazole-terephthalamide) (PBIA) fibers, a kind of heterocyclic aramid fibers, possess extraordinary mechanical properties and advanced applications in aerospace, military protection, and other civilian areas. However, harsh application scenarios are putting forward even stringent requirements for the mechanical performances and environmental compatibility of PBIA fibers. Strengthening lateral interactions between polymer chains are approachable methods but ongoing challenges to obtain PBIA fibers with high-performance. This work develops a novel holey reduced-graphene-oxide (HrGO)/PBIA composite fiber with a scaffolded structure, in which the HrGO plays a role of clamp to effectively band plentiful PBIA chains through the in-plane holes. A small amount of HrGO (0.075 wt%) is able to improve the tensile strength and Young's modulus of HrGO/PBIA fibers by 11.5% and 8.3%, respectively. The small amount of well dispersed HrGO improves the crystallinity and serves as the topological constraint that enhances the lateral interaction of the PBIA chains, which is unveiled by the wide-angle X-ray scattering and the coarse-grained molecular dynamics simulations. In addition, the favorable compatibility of HrGO/PBIA fibers in complex application scenarios is demonstrated by the dynamic and cyclic-loading measurements.