Enhanced multifunctional performance of epoxy enabled by low-loading meta-aramid fibrids

Aramid fibers serve as promising reinforcing fillers for fabricating epoxy composites. However, their smooth surface and lack of reactive functional groups lead to poor interfacial adhesion with the epoxy, thus restricting the improvement of multifunctional properties. In this study, micro-fibrillated meta-aramid fibrids (MAFs) were fabricated and incorporated into epoxy. Featuring a unique film-network structure, MAFs can generate strong interfacial interactions with epoxy, while also exhibiting inherent advantages in mechanical strength, insulation properties, and thermal stability. Adding only 0.1 wt% of MAFs, the toughness and tensile strength of MAFs/Epoxy composite dielectrics increased by 108.9% and 39.8%, respectively, owing to the effective load transfer enabled by MAFs. The MAFs/Epoxy composite dielectrics exhibited an 11.72% higher breakdown strength compared to epoxy, with volumetric conductivity reducing from 7.03 × 10⁻¹⁴ S/m to 6.70 × 10⁻¹⁵ S/m. This improvement is primarily due to the occurrence of abundant deep traps introduced by MAFs. Meanwhile, the initial energy storage modulus (3013.52 MPa) and T_g (125.93 ℃) of MAFs/Epoxy composite dielectrics were significantly improved, attributed to effective mechanical interlocking between MAFs and epoxy. The incorporation of MAFs at low loading levels enhances the comprehensive performance of epoxy composites. This strategy provides critical insights for developing multifunctional epoxy composites and meeting the requirements of advanced electrical equipment development.