GO-PPDA modified and aligned PBO fibers for high-performance insulating core-rod composites

Composite insulators for high-voltage power grids are subject to multiple constraints concerning thermal conductivity, mechanical load-bearing capacity, and electrical insulation reliability. Poly(p-phenylene benzobisoxazole) (PBO) fibers are considered an ideal reinforcement phase owing to their excellent mechanical strength, thermal conductivity, and electrical insulation properties, but their smooth and inert surface results in poor interfacial adhesion with the epoxy resin matrix. Moreover, the lack of PBO fibers alignment control limits the full exploitation of their thermal conductivity for high-voltage insulation equipment. In this study, a synergistic strategy was developed to modify the PBO fiber surface with aminated graphene oxide (GO-PPDA) and to align the PBO fibers to enhance the interfacial, mechanical, and thermal properties of the resulting fiber-reinforced composite. In experiments, the interfacial shear strength (IFSS) was increased to a maximum of 57.62 MPa, representing a 54 % improvement over untreated fibers. Molecular dynamics simulations confirmed, at the atomic scale, that the interfacial binding energy was significantly enhanced after GO-PPDA modification. The thermal conductivity of the composite with aligned fibers reached 1.531 W m −1  K −1 , which is dramatically higher than that of its randomly oriented counterpart.Optimized amination also improved breakdown strength to 32.5 kV mm −1 while effectively suppressing dielectric loss. Moreover, electrostatic field simulations confirmed that the introduced uniform GO-PPDA contributes to electric field homogenization. Furthermore, the flexural and tensile strengths of the composite were enhanced by 147.9 % and 224.4 %, respectively. This study provides a systematic design strategy for the development of high-performance insulating core rods for composite insulators.