Phenolic Resin‐Assisted Shear Exfoliation Preparation of Graphene Nanosheets to Enhance Mechanical and Thermal Properties of Epoxy Resin Matrix Composites

Abstract

Epoxy resin (EP) is widely used in engineering owing to its excellent mechanical properties, chemical resistance, and thermal stability. However, its high crosslinking density after curing often causes inherent brittleness, limiting its use in advanced structural materials. To address this limitation, this study developed a novel approach for fabricating graphene‐reinforced epoxy composites through phenolic resin (PF)‐assisted ball milling. Large and thin GNs were obtained, with a representative nanosheet exhibiting a lateral dimension of approximately 5 μm, a thickness of approximately 3 nm, and an aspect ratio of approximately 1667. The GNs/PF/EP composites were prepared by directly incorporating the milled GNs/PF mixture into the epoxy matrix at room temperature. The incorporation of PF and GNs enhances compressive deformability, thermal conductivity, and compression‐recovery performance. Notably, the composite achieves approximately 60% compressive strain under 80 MPa compressive stress and recovers to approximately 97%–99% of its original height within 160–180 s after unloading. Furthermore, at a GNs loading of 2.14 wt%, the composite shows a 22.1% improvement in thermal conductivity compared with pure epoxy. These properties make the composites suitable for protective coatings, construction interlayers, and automotive components requiring combined mechanical resilience and thermal management.